https://www.theverge.com/2018/3/20/17142806/how-to-delete-facebook-page-account-data-privacy

If you’ve finally given up on the world’s most popular social media network and want to get rid of Facebook, it’s not too complicated to remove yourself from the service. But before you delete all of those pictures, posts, and Likes, you should download your personal information from Facebook first.

Your Facebook archives contain just about all of the pertinent information related to your account, including your photos, active sessions, chat history, IP addresses, facial recognition data, and which ads you clicked, just to name a few. That’s a ton of personal information that you should probably maintain access to. To download your archive, go to “Settings” and click “Download a copy of your Facebook data” at the bottom of General Account Settings, and then click “Start My Archive.”