Open the Facebook app on your mobile
Tap the menu icon
Go to Settings & privacy
Tap Settings
Tap Accounts Center
Tap Personal details
Tap Account ownership and control
Tap Deactivation or deletion
Select the Facebook account you want to delete
Choose Delete account
Tap Continue
Follow the on-screen prompts
Enter your password if asked
Confirm permanent deletion
Download your information first if needed before deleting
Log out after confirming the deletion request