Hi there Alshaimaa Alanadoly!
Thank you for posting in Apple Communities. It sounds like your are having trouble using Touch ID on your Mac. We can give you some steps to point you in the right direction towards a solution.
To start, are you using macOS 11.2? If so, let's have you update to macOS 11.2.3 Big Sur to make sure that your MacBook Pro benefits from all improvements. For steps, look here: How to update the software on your Mac
Does the issue persist if your power adapter is connected to your Mac? If not, reset your SMC using the steps listed here: How to reset the SMC of your Mac These steps can help resolve certain issues on the Mac that may be related to power.
If you are still having trouble test the issue in safe mode: Start up your Mac in safe mode Safe mode can help you determine if the issue is related to any software your Mac uses while starting up.
Still no luck? Reach out to our support Advisors here: Get Support
We hope this helps.
Cheers!