recording quality for copyrighting

by Amber

I have written lots of songs over the years and since I don't have the means to professionally record them, I have decided to try and sell some of them. I know the first step is to copyright them, my question is how well do they need to be recorded for that purpose? Can I just do a basic voice and guitar version or do they need a full arrangement? I will be doing all the recording myself and am just learning , so how simple can I go just to license songs with the copyright office? Thanks ! Amber : )