I don't remember my iPhone Apple ID

Unfortunately, it sounds like you've encountered Activation Lock an anti-theft mechanism set by a prior owner of the phone.

Until THAT owner releases the lock, the phone will remain unusable.

See how to release the lock in this article:

How to remove Activation Lock - Apple Support

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Hello ~ You will need to reach out to the person that gave the iPhone to you. They will have to follow the steps here:

What to do before you sell, give away, or trade in your iPhone ...

You cannot remove the activation lock and neither we nor Apple can. If you cannot contact the previous owner or they cannot or will not remove the lock recycle it responsibly. Take a look here for more information:

Activation Lock for iPhone, iPad, and iPod touch - Apple Support

Also:

The All Too Common SAD Reality of Buying a Used iPad/iPhone

~Katana-San~