Getting into my old iphone

Are you seeing an Activation Lock?

If you have changed your ID or password, have you followed the steps in this article?

What to do after you change your Apple ID or password - Apple Support.      

If necessary, if you are the original owner, contact Apple ID Support. They will need to see the original purchase receipt with the serial number/paperwork.

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. 

https://twitter.com/AppleSupport

Do you have additional information that might help us help you? See what Eric says above. But, is the Apple ID related to and old iPhone you acquired used. If yes, then note that activation lock can be turned off only by entering the correct Apple ID/password combination. The correct combination is in the one used in setting the device up prior to activation lock being enabled. If activation lock is being shown, then we cannot help you and the iPhone will be useless to you. Post back if activation lock is not your problem and you have additional information for us as noted above.