What are the rules on sleepovers?

[Bryyy]

My almost 10yo would like a sleepover for her birty but I really can't find any guidy about it. Might best guess is that she can only invite one friend over.

My dd is also 10. We had a garden party in Aug with a disco dome then her best friend stayed over.
The week before she went to a party and stayed over, again bbq garden party. There were 6 of them but they had their own individual teepees to sleep in.

We're going to Orlando whenever possible. She wants to go on a shopping trip but it's a big break as we live so remotely. But for the most part I think she want to hang out with her friends.