Ladybug: Hi it's me Ladybug!
Cat Noir: And me!
Ladybug: Go away.
Cat Noir: But this is both of our account
Ladybug: Fine stay here...

Their Username Miraculous is for ladybug and Noir is for Cat Noir.

Follow us both
Marinette_TheLadybug
and
CatNoir_Adrein