you need the following documents

1. No objection letter from your office stating they have no objection on you bring your spouse to doha.

2. Salary Certificate (this is optional, but recommended).

3. Passport copies of yourself & your spouse.
Your passport copy should include the pages with your details and also the page of your qatar resident permit (iqama). Your spouse's passport copies should contain pages with her details. Page which contains the spouse's name would help a lot.

4. Copy of marriage certificate (optional).

5. Immigration form to apply for visit visa duly filled in.
you may download it from here -
http://www.moi.gov.qa/site/arabic/departments/PassportDept/resources/200...

Go to Immigration office at Gharaffa, Gate No 4(four) - Expatriate Affairs Section

In morning, try to go before 6:30am
In afternoon, try to go before 2:30pm

Sometimes they require you to get approval from Immigration officer & they will direct you to his office. After you get the signature, submit your application for visa.

They will charge you QR200/- for it. ONLY E-CASH or Debit Cards (ATM) or Credit Cards are accepted.

Hope this helps in securing the visit visa.

best of luck