forgot Apple ID and password

Hey there, shahrina113.

After reviewing your post, we understand that you erased your iPhone and now possibly seeing the Activation Lock screen with an unknown Apple ID. It's important that you're able to get past that screen and use your iPhone.

Have you ever changed your Apple ID email address? If yes, you could try using that email address as well.

Also, you can read more about Activation Lock and how to turn that off here: Turn off Activation Lock

Take care.

You need a copy of the original purchase receipt with the serial number on it.

If you are the original owner, contact Apple. Apple can remove the Activation Lock if provided the required paperwork. Either take the device, the original purchase receipt with the serial number, and a photo ID to the nearest Apple Store (if it has reopened)

Genius Bar Reservation and Apple Support Options - Apple.    

or contact Apple ID Support. 

 Apple ID - Official Apple Support.    

Contact Apple for help with Apple ID account security - Apple Support.  (Link doesn’t always load)   

Get Support      Work through the screens to get a chat option. 

Apple Support schedule phone call

https://twitter.com/AppleSupport       People have posted it may take an hour or more to get a response.

Follow the steps Eric Root gave. However, it's best to call/chat Apple. Not all Apple Stores can do Activation Lock removal in store and my understanding is they are not supposed to do it in store as there is a specific team that approves them and it can take a few days.