Facebook is a website, and all the data for your page is stored on various Facebook servers in giant data centres. It is not stored on your PC or on your phone: they are just ways to access it online.
The Facebook help page says:
When you delete your account, people won’t be able to see it on Facebook. It may take up to 90 days to delete all of the things you’ve posted, like your photos, status updates or other data stored in backup systems. While we are deleting this information, it is inaccessible to other people using Facebook.
Before you delete your Facebook page, it’s a good idea to download a copy of your data. To do this, click the downward-facing triangle and select Settings from the drop-down menu. When the page loads, click the text that says “Download a copy of your Facebook data.” Facebook will email you when your data is ready to download.
Otherwise, consider deactivating your account rather than deleting it. The effect is exactly the same as far as your friends are concerned: you and your data disappear from Facebook. However, you can re-activate your account if you change your mind.
Making a fresh start
Before you delete your account, get a back-up of your data, as described above. After that, go to your account settings and change the key entries to something you don’t want. It’s most important to change your email address to another working email address — you can create one for the purpose. You can also change your real name, your user name, and possibly your password. (Changing your password will stop your smartphone and tablet apps from logging in.)
The settings for “Account security” may also contain a list of “registered devices” that are associated with your account. You may want to remove those as well.
Remember, when you create a new account, Facebook will do its best to reactivate your old account, based on whatever data was in the old account.
Now you should eventually be able to create a new account, with your preferred email address and user name. This wouldn’t expect this to work until your old information has been flushed from Facebook’s system. That could take about two weeks, but it might take a month or more.
A version of this article appears on March 17 2016 of The Guardian.