Hello Caitlin123_,
We understand you're having an issue with signing into your Mac. We're here to help!
The steps below will provide you some help to reset your Mac password so you're able to sign into it again.
Reset your login password using your Apple ID
If you associated your user account with your Apple ID, you can use your Apple ID to reset your login password.
1. Click the question mark
next to the password field.
2. If you don’t see a question mark
, press and hold the power button until your Mac shuts down, then press the power button to restart your Mac.
3. Click the arrow
next to “reset it using your Apple ID.”
4. If you don’t see an arrow
, see the Apple Support article If you can’t reset your Mac login password.
5. Enter an Apple ID and password, then click Next.
6. Follow the instructions to reset your login password.
If you don’t remember your Apple ID password, see If you forget your Apple ID or password.
To learn how to reset your Mac password by using a recovery key then check out this article which also contains the information above: Reset your login password using your Apple ID
If you associated your user account with your Apple ID, you can use your Apple ID to reset your login password: Reset your Mac login password
Have a great day!