Let's just say you decide your Facebook account no longer serves a purpose. Here's what you do!
Step 1: Backup all of your data
First of all, it’s time to backup all posts, videos and photos.
Click the “down arrow” in the upper right-hand corner
In General Account Settings, Click ‘download a copy of all your Facebook data’, download archive.
Step 2: Deactivate your account
Click the “down arrow” in the upper right-hand corner, account settings, click security on the left menu, then click deactivate your account.
Step 3: Delete your Facebook account
Click on the “lock” icon in the upper right-hand corner, click the “magnifying glass” icon and then search for “delete”.
Click on the result near the bottom that says “How do i permanently delete my account”. Now scroll down till you see the “Let us know” link. Click the delete my account. Put in your password, submit captcha. Hit OK. That’s it.