RolePlay MCPE servers give their players option to pick their Role and then play with others. RolePlay Minecraft PE servers have various themes and Roles they have are usually based on MCPE server theme.
Difference between RolePlay servers and Creative servers?
Creative MC PE servers usually allow players to host their own RolePlay events, meanwhile on servers meant only for RolePlay you can't switch your gamemode, you have to pick your Role and play with it. But the good thing is RolePlay servers tend to have plenty of different Roles that are fun to play.