apple ID

Use the 2nd link Androish posted and try all the email addresses you can think of.

If necessary, if you are the original owner, take the device, the original purchase receipt with the serial number, and a photo ID to the nearest Apple Store.

Genius Bar Reservation and Apple Support Options - Apple. https://www.apple.com/retail/geniusbar/

or contact Apple ID Support. They will need to see the original purchase receipt/paperwork also.

Apple ID - Official Apple Support. https://support.apple.com/apple-id

Contact Apple for help with Apple ID account security - Apple Support. https://support.apple.com/en-us/HT204169

Get Support https://getsupport.apple.com/. Work through the screens to get a chat option.

https://twitter.com/AppleSupport

Or fill out and submit iTunes Store - Contact Us - Official Apple Support https://support.apple.com/en-euro/itunes-contact The form is for iTunes, but it will get passed to the ID Support section.

Start with following these two articles:

If you forgot your Apple ID password - Apple Support

If you forgot your Apple ID - Apple Support

Good luck!

Where are you trying to log in? What happens when you try? Error message(s)? More information would help.