medical needed for employment visa

Before you can get a medical certificate for employment in Oman you must go to GAMCA office first and present your passport, then they are going to assign you  to an accredited clinic.
With regards to visa they can send it via email and have it printed out. But if you're a direct hire OWWA would be asking an original copy of offer letter from the company in Oman. Your employer can send it to you via fedex. Also, you'll have to submit letter to POEA/OWWA on how did you come about to get hired by your employer. But if you were hired thru an agency they'll do all the works for you.

Actually, I have already my employer in Oman willing to give employment visa,but they told me I undergo a medical here and send to them for my visa processing.i know its needed.bcoz I was there working before.

But,my question is. Is it ok,i my self will do process in OWWA/POEA?Bcoz before I think its ok, I had a friend doing that his employer in Dubai send him the original visa and contract.