you cant "save it" per se, but you can:
a) disable spellichecking from Tools / Options.
b) have it ignore each "error"
c) add the words to your library (like a rare last name, etc).
however, whatever it is, it will only apply to your computer. if you're planning on sending it to someone else, he/she will have those green / red lines no matter what you (short of writing a macro that would disable those functions every time the file is opened, but you dont wanna do that to your potential employer)
not to the best of my knowledge. however, you can save your resume in PDF format - it wont highlight anything.