Dear friend;
If you are newly got job then you should have offer letter(contract letter) with you should be attested with chamber of commerce and Ministry of foreign affairs.But if you are already hav e been working here in saudi in any company then no need all these formalities...Only on a piece of paper company will provide you several details: name,passport number,Iqama number,profession etc..
With the attestation of Chamber of commerce...IT will be more than enough to attest your certificates...