I moved to the UK in August of 2012 and am not sure if I filed that year or not, I did not file in 2013 but have been filing since then! I do not make enough to actually owe anything but I was wondering (incase I move back) if I need to file for those years? I basically earned nothing in 2012 and 2013 but know that might not matter. How do I go back and file? Do I need to? I've not taken a return in the past 5 years so not looking for one... Just want to make sure I've got no problems applying for jobs in the USA.
If you made enough income in those years to be required to file and failed to do so, then you should file them. You can access prior years forms and instructions in the link below.