To permanently delete your Facebook account, go to the Facebook settings page and click on the “Delete My Account” link. You will be prompted to enter your password one last time before you can officially delete your account.
This question has been answered in the following Quora article: https://www.quora.
Open Facebook on your computer. Click the down arrow in the top right corner of the screen and select Settings. Scroll to General. Under General, click on Manage Your Account. Click Delete My Account. Enter your password and click Continue. Review the information on this page, including what will happen to your account, posts you’ve shared, photos you’ve uploaded, friends you’ve made, etc., then click Delete My Account again to confirm deletion of your account.
When you delete your Facebook account, all your Facebook data will be permanently deleted and no one will be able to see it. The only exception is if you’ve shared this data with someone else.
You cannot delete the Facebook account of another person. You can only deactivate it, which means that they will no longer be able to log into it or post anything on their timeline.
To delete your Facebook account without password, you need to request Facebook to delete your account. The process can take up to 90 days. To do this, go to the help center and select “Delete my account”.
The process of deleting Facebook on a mobile phone is pretty straightforward. To delete Facebook on an Android device, open the Settings app and choose Apps. Find Facebook, then tap the Uninstall button. On iOS, go to Settings > General > Profiles & Device Management > your Apple ID > Delete App.
If you are using a Mac, go to System Preferences > Security & Privacy > General tab. Click on “Edit” and then “Delete from my Mac.”If you are using a Windows PC, go to Control Panel > User Accounts and Family Safety > User Accounts. Click on the account that you want to delete and select “Remove Account.
If you have not deleted your Facebook account, but mistakenly deleted a post or photo, it may still show up. If you’re sure that you’ve deleted your account and everything associated with it, then there’s likely an error on Facebook’s end.