Hello, Navid—and welcome to English Forums.

You can start by reading this:

thank you sir

I read this but my problem is Im going for my internship in automotive company and i don't what should i explain for them because I study different course . and I been working for long time in different company but they are not related to car design but, it was all about design and graphic design and printing .
if its possible I send you by E-mail what I wrote but its very poor in grammar b

I charge money for personal editing. See my profile. However, I see no reason why you should not post it here; just use false names.