How old should your children be for social media accounts?

How old must your child be before you let them have a social media account?

Are there some accounts they are absolutely not allowed to have?

Allegedly, some social media has a minimum age of 13 (a lot of kids get around this by lying about their ages). We stuck with that: when each of our girls turned 13 we set them up, sending “friend” requests to us (my husband & I share a page), family, and any of their friends who already had it. It worked for us.