I was wanting to find out if I can
swap my 12a rotor for a 13b turbo
I know were one is it comes with tranny and wire harness

 

The short answer is yes.

For the rest of it if you do it this question has been asked so many times that we cannot even count that high

You will find detailed information if you pursue this in the Archive section.
If searching in this section just key in the keyword Turbo.

The first link is to the FAQ section.
https://www.rx7club.com/1st-generation-specific-1979-1985-18/1st-gen-rx-7-faq-page-237777/

The 2nd link is to another section that will answer some basic questions and get you acquianted with how this section works.
https://www.rx7club.com/1st-generation-specific-1979-1985-18/rules-1st-gen-section-89820/

Best thing that you can do for yourself when you are new is do alot of reading.