How do I combine the desktops? I migrated my old laptop to my new Mac Air and don't want to have to log out and log in to access migrated information.

I recently got a new MacBook Air. I migrated all my information from my old laptop (Dell Inspiron) to my new laptop. Is there a way to combine desktops (I think is what they're called) so I don't have to log out of one and into the other to access the information on it? I'm a brand new Apple user, aside from an iPhone, so am trying to learn the ropes. Any helpful suggestions would be greatly appreciated! Thank you!