For a long time, Roblox has had a somewhat mediocre rig builder. Not anymore! Roblox has added a variety of options including instancing your own character without the use of external plugins. This is nice quality of life update for developers.
Rig Builder Documentation: https://create.roblox.com/docs/building-and-visuals/studio-modeling/rig-builder
Facial Animation Documentation: https://create.roblox.com/docs/avatar/facial-animation
