2 iphones

Yes, but they'll share everything. Calls, Messages, icloud data, photos (if using iCloud photos) etc ...

If you plan on using both phones, this should not be an issue, if the other phone is meant for someone else, they should use their own Apple ID.

Yes, if you are the same person using the 2 iPhone.

If you tell us what you are trying to do, we can help you better.

Hi Caya7982,

Yes, you can! Sign in with your Apple ID - Apple Support

Cheers,

Jack