Images of tax, banking or wire transfer forms containing sensitive information can easily be viewed by anyone with physical or remote access to your machine. Unfortunately, macOS Preview doesn’t support file-level password protection, but there is a quick workaround that don't require third-party software.
By converting your graphics file to a PDF, you can unlock a handy password feature tucked away in its settings, turning your image into an encrypted password-protected PDF. This takes just a few seconds.
• Right-click the image you want to password protect, hover over “Open With,” and choose Preview
• Go to File > Export...
• Name your file, choose its location on your machine, choose PDF as format and click "Permissions..." to give you more options, including the one to add a password to the file
• Check the “Require Password To Open Document” box
• Enter the password
• Set permissions to allow actions and/or changes to be made without entering the "Owner Password"
• Enter the "Owner Password" required to allow any actions and/or changes not selected in the Permissions section
• Click on “Apply” and then click “Save”

Here are three useful tips that will ensure you do not face this issue on your Mac.
Add a password hint
After you add a password hint, it shows up on the screen if you enter the incorrect password a few times. You can see that hint and instantly recall what your Mac’s login password is.
A hint should be there to help you refresh your memory. Do not put your exact password or make it too obvious that others around you can guess it.
You can add the hint when you’re creating or changing your Mac’s user account password. Here’s what to do if you’d like to add one now:
• Go to Apple menu > System Settings... > Users & Groups
• Click the info icon (i) next to the desired account
• Click Change... next to Password
• Create a new password and add the hint on this screen
• Lastly, click Change Password
Once the hint is added, go to System Settings > Lock Screen and turn on the switch for “Show password hints”.
Show a Lock Screen message
The Lock Screen message is not for adding password hints but rather for displaying a welcome message. You can for example add your email address/phone number so someone who finds your misplaced Mac can contact you and return it.
However, if you do not want to change your current Mac password – a requisite for adding password hint if you don’t have already – then you can rely on the Lock Screen message feature to add a hint. But again, don’t make it obvious.
• Launch Cocktail (https://www.maintain.se/cocktail)
• Click the Interface toolbar button
• Go to the Login tab
• Enter your message into the "Display additional message" text field
• Click Apply
Allow Apple ID to reset Mac’s password
This is an extremely important step that will be helpful if you’ve forgotten your password and can’t figure it out even after looking at the hint.
Go to System Settings > Users & Groups and click the info icon (i) next to an account. Now, turn the switch for “Allow user to reset password using Apple Account”
From now on, you can use your Apple ID and password to reset your Mac’s forgotten account password.

Using removable media, such as USB flash drives or removable disks, is a convenient way to transport information. However, if the removable media is lost or stolen, someone else can access its data by mounting the media on another computer.
If you want to keep private or confidential information secure on removable media, you need to encrypt the information on it.
WARNING: When you encrypt a disk or other media, the disk format is converted to the APFS format and then encrypted. Macs with earlier versions of macOS that don’t support the APFS format are not able to read the device’s data. Consider whether you need to connect the media to a Mac with an earlier version of macOS before you encrypt the data. You can also update your other Mac to the latest version of the macOS that supports the APFS format.
To protect your removable media with encryption:
• On your Mac, click the Finder icon in the Dock to open a Finder window
• In the sidebar, Control-click the item you want to encrypt
• Choose Encrypt [item name] from the shortcut menu
• Create a password for the disk and click Encrypt Disk
Be sure to record and keep this password in a safe place. You cannot access the data on the encrypted disk without it.
It may take some time to encrypt, depending on how much information is stored on your Mac. However, you can use your Mac as usual while the disk is being encrypted. To decrypt an encrypted disk, Control-click the disk you want to decrypt, then choose Decrypt [item name] from the shortcut menu.
Like most technology companies, Apple stores information about you on its servers. Unlike most technology companies, however, Apple does not store identifiable information such as locations, instant messages, and so forth. Thanks to Differential Privacy techniques, Apple can build smart services without using the cloud for insight, keeping information about each individual user completely private.
The list of personally identifiable things Apple knows about you is rather short compared to other technology companies. Identifiable information Apple knows about you includes the following:
• Apps you’ve downloaded
• A log of every time you updated your installed apps
• Movies, books, and other media you’ve downloaded
• All of the songs you’ve stored in iTunes Match
• In-app purchases you’ve made on your devices
• All the devices you’ve bought from Apple, along with their serial numbers
• A log of every AppleCare support query you’ve made
• A repair session log of what was damaged
• Serial numbers for both the old and replacement parts
Your archive does not contain identifiable data already included within your Apple ID account, such as calendar content, your iCloud emails, iTunes content, and so forth.
To download your Apple data archive:
• Visit the Apple Privacy Policy webpage at privacy.apple.com and sign in using your Apple ID and password
• Click "Request a copy of your data" under the Manage your data > Get a copy of your data section
• Choose the data you want to download
• After selecting what you want to download, click the "Continue" button
• Select a maximum file size for each file (irrespective of what you choose, you will get all the data)
• Click "Complete request"
You have now successfully requested Apple for your data. They will notify you on your Apple ID email address in about seven days. Once you receive the email, click "Get your data" within the time frame mentioned at the top of the email. Sign in with your Apple ID, and you will see the "Download your data" screen. Click the little download icon next to the data types to download them locally to your computer (open the ZIP file and dive in to see your data).

Resetting an Apple ID password can be annoying, though it’s made much easier if you have access to a device that you are already signed into. Without another device though, the process of resetting an Apple ID account login can be frustrating, but a Recovery Key makes this situation easier.
Apple ID Recovery Key serves as an additional way of authenticating your Apple account, and it can be used if you forget your password and lose access to another trusted device. Using a recovery key eliminates the need to visit Apple’s website to jump through hoops like verifying payment method details and answering security questions for a password reset. The ability to generate a recovery key from the Mac requires macOS Big Sur or macOS Monterey.
If you have a Mac, it’s pretty easy to generate and use a recovery key.
• Open “System Preferences” on the Mac (from Apple menu or Dock).
• This will open a new window on your Mac. Click on the Apple ID option located at the top-right corner.
• Now, click on “Password & Security” from the left pane. In this section, you’ll find the Recovery Key option below Trusted phone numbers. Click on “Turn on” next to the Recovery key option to continue.
• When you’re prompted to confirm your action, click on “Use recovery key” to proceed.
• Next, you’ll be asked to enter your Mac user password. Type in the password and click “OK”.
• If you have an iPhone, you’ll also be prompted the enter the passcode you use to unlock your iPhone.
• Now, your unique recovery key will be shown to you on the screen. Make sure to write it down in a safe place that you’re able to easily access. Once you’re done, click on “Continue”.
• Next, you’ll be asked to enter your 28-character recovery key to verify that you’ve noted it down. Click on “Done” after typing it in.
• The feature is now turned on. If you want to change the recovery key for any reason, you can click on “Create new key”. You also have the option to turn this feature off at any time.
From now on, you’ll have just two ways to reset the password for your Apple account. You can either reset the password from a device that you’re already logged into, whether it’s your Mac, iPhone, or iPad, or you can use the recovery key instead. The latter could prove to be invaluable if you don’t have access to another trusted device, or if you only have one Apple device.
Note that when you disable and re-enable the Recovery Key feature, a completely new key will be generated for your account. If you lost your current recovery key somehow, you can replace the key with a new one on your Mac from the same menu using the “Create new key” option.