Depends on the purpose of usage, see below info:

Conditions for granting of a certificate of good conduct
(Police Clearance)
Classified according to the purpose for which it is granted
________________________

Firstly: For the purpose of submission to ministries, companies, and Government institutions for employment.
A- Conditions for Qatari people (men and women):
The following documents must be brought:

1- A letter of recommendation to work from the ministry, institution, or company which the person shall work for should be directed to the Director of Criminal Evidence and Information Department.
2- A copy of ID card.
3- 3 photographs size (4X6cm)
4- Fees: a 5 Riyals category revenue stamp.
5- A copy of secondary certificate (for men)
6- A letter of non-objection to work in government departments issued by the Armed Forces of Qatar for people under the age of 30 and they did not obtain the secondary certificate (for men) and did not work in the Armed Forces or the Ministry Of Interior.
7- A copy of the resign paper or a no obligation letter from the last job you had if applicable.

B- Conditions for Gulf country citizens.
The following documents must be brought:

1- A letter of recommendation from work.
2- The Passport and Qatari ID card (if available) and a copy of both cards as well.
3- 3 photographs size (4X6cm)
4- - Fees: a 5 Riyals category revenue stamp.
5- A certificate of good conduct issued by the concerned authorities from the applicant's country and documented by the concerned authorities and validated by Qatar's Ministry of Foreign Affairs or from the country representative. Excluded from this (those who have been born in Doha under the condition of bringing a copy of Birth certificate, and who entered the country under the age of 13 under the condition of bringing a copy of passport indicates the date of their first entrance to Qatar).
6- A letter of non-objection from the guardian or the sponsor for women and a copy of the passport.

C- Conditions for residents from other nationalities (men and women):
The following documents must be brought:

1- A letter of recommendation from work.
2- The Passport and Qatari ID card (if available) and a copy of both cards as well.
3- 3 photographs size (4X6cm).
4- Fees: a 5 Riyals category revenue stamp.
5- A letter of non-objection from the sponsor.
6- A letter of non-objection from the sponsor for women and a copy of the sponsor's passport.
7- If the husband works in the Armed Forces or the Ministry Of Interior he must present a prior approval letter from his work headquarter for the wife to work for the concerned authorities.
8- - A certificate of good conduct issued by the concerned authorities from the applicant's country and documented by the concerned authorities and validated by Qatar's Ministry of Foreign Affairs or from the country representative. Excluded from this (those who have been born in Doha under the condition of bringing a copy of Birth certificate, and who entered the country under the age of 13 under the condition of bringing a copy of passport indicates the date of their first entrance to Qatar).

Secondly: For the purpose of submission to: other authorities (To the Customs Department "to work in custom clearance", to the Ministry of Justice "For opening law offices", the Ministry of Finance "exchange companies" and the Ministry of Finance "Veterinarians", etc......for other purposes other than employment.

A- For Qataries:

1- A letter from the concerned authority or personal letter (under specific cases).
2- A copy of ID card.
3- 3 photographs size (4X6cm).
4- Fees: a 5 Riyals category revenue stamp.
5- If the applicant works in the Armed Forces or Police he must bring a letter from the headquarters of work in order to issue the certificate.
6- A certificate of good conduct issued by the concerned authorities from the applicant's country and documented by the concerned authorities and validated by Qatar's Ministry of Foreign Affairs or from the country representative. Excluded from this (those who have been born in Doha under the condition of bringing a copy of Birth certificate, and who entered the country under the age of 13 under the condition of bringing a copy of passport indicates the date of their first entrance to Qatar).

B- For residents:

1- A letter from the concerned authority and the sponsor.
2- The passport and Qatari ID card and a copy of both cards.
3- 3 photographs size (4x6).
4- Fees: a 5 Riyals revenue stamp.
5- A certificate of good conduct issued by the concerned authorities from the applicant's country and documented by the concerned authorities and validated by Qatar's Ministry of Foreign Affairs or from the country representative. Excluded from this (those who have been born in Doha under the condition of bringing a copy of Birth certificate, and who entered the country under the age of 16 under the condition of bringing a copy of passport indicates the date of their first entrance to Qatar).

** for women: a letter of non-objection from her sponsor at work plus a copy of the sponsor’s passport and a prior approval letter from the husband work if the husband works in the Armed forces or Police.

C- If the applicant is out of the country after the Qatar's resident permit expires he/she must send the following documents for granting a certificate of good conduct.

1- A personal letter states the purpose for granting a certificate of good conduct.
2- A copy of passport indicates the date of the first entrance to Qatar and the final departure.
3- 3 photographs size (4X6cm).
4- Fees: 8 US dollars (by cash or check).
5- A certificate of good conduct issued by the concerned authorities from the applicant's country and documented by the concerned authorities and validated by Qatar's Ministry of Foreign Affairs or from the country representative. Excluded from this (those who have been born in Doha under the condition of bringing a copy of Birth certificate, and who entered the country under the age of 13 under the condition of bringing a copy of passport indicates the date of their first entrance to Qatar).
6- Fingerprint form validated by the concerned authorities of the applicant's country.

Thirdly: for the purpose of submission outside the country in the case of immigration or doing business or for study or for any other purpose:

A- The following documents must be brought by Qataries:
1. A personal letter indicates the purpose for granting of the certificate of good conduct.
2. A copy of the Passport and Qatari ID card.
3. Fees: a 5 Riyals category revenue stamp.
4. 3 photographs size (4x6).

** The following documents must be brought if the applicant is a resident:
1- A personal letter states the purpose for granting of the certificate of good conduct.
2- The passport and ID card and a copy of both cards.
3- 3 photographs size (4x6).
4- Fees: a 5 Riyals category revenue stamp.

SOURCE: MINISTRY OF INTERIOR