I think you're asking two questions here, if I understand correctly. The first one is "how do you get a trademark registration?" The answer to that is that you need to file a registration application with the USPTO (state registrations are also available and may be useful, but they are comparatively unimportant). It is always a good idea to hire a trademark lawyer for that. You don't HAVE to file a registration for every mark you use, but your rights (e.g., to prevent others from using the mark) will be more extensive if you do. The second question is "how do you transfer the owenership of the marks from you, personally, to the LLC?" That can be done as a straight assignment (sale), where you would transfer ownership by a fairly simple written agreement. Or, you could assign the mark by way of a license. Either is pretty easy to do for a lawyer with any experience in Intellectual Property.
Patrick Maslyn
Maslyn Law PLC
www.maslynlaw.com