Friend,
To get a Schengen (European countries) Visa you need the following documents.
1. Valid passport having return visa.
2. Financial statement (important from bank with) shows your salary.
3. Invitation letter from a resident or company attested by Chamber and sent directly to Embassy in Qatar and apply with your copy.
4. Return ticket.
5. Travel and health insurance.
6. Your employer's confirmation letter which includes your salary and guarantee that you will come back to Qatar after visit.
When I applied for a Schengen visa, I submitted all the above documents to get visa.