If you’re in Desktop, simply go to Facebook’s
or direct link here: https://www.facebook.com/settings?tab=security§ion=memorialization&view
Once you send the request, your selected person will get notification message about this.
After Legacy Contact is set, you may tick the option to allow them download your copy of Facebook includes posts, photos, videos, and info in About section. Messages won’t be include.
If you’re in Mobile, here are the screenshot on where to set Legacy Contact.
This is something like a virtual Will, share around with your friends & families member to have their account get connected. So that their husband, wife, father, mother, brother, sister, other relative, or friends can get to update their last message, just in case.
Cheers, with love.