I need to change something in my system preferences and need admin password. I forgot it. What can I do?

Reset your password:

https://support.apple.com/en-us/HT202860

https://support.apple.com/guide/mac-help/reset-your-mac-login-password-mh35902/mac

Wedding1231 wrote:

I need to change something in my system preferences and need admin password.

ow to reset administrator password on Mac?

If you are the only user on the machine—Admin password is typically your user password to log into your account.

You can make changes to this request:

Change Security & Privacy General preferences on Mac ...