Anyone has changed my id apple, how can i access my Mac?

Hey there and welcome to Apple Support Communities Thanhthuanngo,

We can certainly understand your concern and see you came to us from the article If you forgot your Apple ID password .

We recommend checking out these steps for more information on what to do if you cant log into your iMac.

" If you forgot your Mac login password

If you forgot the password to log in to your Mac user account, or the password isn't accepted, choose a reset option from the login window.

These steps are for macOS Catalina or later. The steps for macOS Mojave or earlier are different. If you're not sure which macOS you're using, try these steps first.

Make sure that you're at the login window

The login window appears after you turn on, restart, or log out of your Mac. It's not the same as the window you might see when waking your Mac from sleep or stopping the screen saver, though it uses the same password.

• If you see Shut Down, Restart, and Sleep buttons, you're at the login window. 
• If you see a Switch User button, click it to switch to the login window.
• If you see different buttons or no buttons, restart your Mac or press and hold its power button for up to 10 seconds, until it turns off. When your Mac restarts or turns on, it starts up to the login window.
• Every Mac has a power button. On laptop computers that have Touch ID, press and hold Touch ID. "

For additional information, check out this link:

If you forgot your Mac login password - Apple Support

These steps will help ensure your device is working with ease and can fix common issues like the ones you’re experiencing. 

Kindest regards!