am not able to activate my phone

Activation Lock is there to prevent theft from devices. If you purchased your phone from someone and not from Apple and the phone is Activation Lock the only way you are going to be able to get passed that is if you get in touch with the original owner and have them remove it from their account. If you are the original owner, you should be able to enter the password information for the Apple ID that it was originally assigned and then you’ll be able to use it again. Without entering the information to the Apple ID that it was assigned to originally then you aren’t going to be able to get past that point. It’s doing what it was designed to do.

Please look at this --> If you can't activate your iPhone - Apple Support

If you are the owner or the owner has shared all information with you then to open Activation Lock:- If it is Activation locked, read here --> Turn off Activation Lock - Apple Support Activation Lock for iPhone, iPad, and iPod touch - Apple Support

Learn how to remove a device from a previous owner's account.

If you are not the owner and do not have the Apple ID and Password then there is no way that you can get into this iPhone unless the original owner shares the Apple ID and password with you.