Use Face ID or Touch ID if it still works
Try your current passcode carefully if you remember it
Erase the iPhone using Recovery Mode on a Mac or PC
Put the iPhone in Recovery Mode
Connect the iPhone to a computer with Finder or iTunes
Choose Restore when prompted
Set up the iPhone again after it erases
Restore your data from an iCloud or computer backup if available
Use Find My iPhone on iCloud.com to erase the device remotely
Contact Apple Support if you cannot restore access
Bring proof of purchase if Apple requests verification