1) If you have access to the account on desktop:
Click the thumbnail of your Profile Photo in the upper right corner of your Profile Page.
Select Account Settings.
Click on Profile Display Settings.
Click on the Permanently Delete Profile button.
2) If you have access to the account on mobile:
Click on the 3 bars in the corner that take you to your account menu.
Tap on Profile Display Settings.
Tap on Permanently Delete Profile.