How can I add team members to a submission? I'm just finalizing the project, but I can't seem to add anyone... Do they also need to be registered at efabless?

You are asked to list the team members in your proposal A piece of text); see the provided examples. There is no need to register them.

I didn't see any option there to add team member. where the team members will be added ?

@vanshika tanwar you can add team details in your design "details" section