Tell us who they are and how they should be drawn. The designer reads everything you write here, asks the rest in the chat, and draws them once you are both happy.
Pick their style
Chosen once, before anything is drawn. The style settles here with everything else — this is the last moment to change it, and the room can be asked in the conversation — and every picture after this one is held to it, because a character drawn in three different media is three characters.