Forgotten iCloud email ID and password
Most people start at https://iforgot.apple.com and work through apple support. Same as if you forgot your bank password or email - you go through the support organization and get your account returned to you. You would need to do that or go though support to reset the Activation lock presuming you can prove you're the original purchaser of the equipment.

See:


https://support.apple.com/en-us/HT201441
How can I bypass Activation Lock?