How many days before applying to extend my family...

The residents in Qatar may apply for short visit visa to their families and relatives to enter Qatar only for one month. However, the relatives who wish to stay longer to have a medical examination within 72 hours for entering the country. the visa can be extended  another 5 months for the relatives of the first class and cousins (mother, father, sons and sister) and for two months for other relatives. The foreigners who wish to bring their families to stay in Qatar may apply for the residence visa in case of bringing them. In case of bringing the wife, you should apply the general administration pf passports and expatriate affairs

The documents are as follows:
-copy of the id and passport of the residence husband valid for 6 months
-a certificate of the husbands company or employer to show the salary and occupation
-a copy of the marriage deed
to bring the wife and sons, the resident must have a valid residence permit, provided with the marriage deed ratified by the competent authorities based on the rules. The conditions are:
- . Governmental employees and semi-governmental agencies shall have family housing from his/her work administration, or he/she shall have a family housing allowance stipulated in the contract of employment, with confirmation on the profession and salary for employees (Applicants) in government and semi-governmental facilities by official letter
3- The employee's profession in the private sector shall be from the professional and technical professions (other than the workers), and the salary shall not be less than ten thousand riyals or seven thousand riyals with a family accommodation and to be working in a technical and specialized professions (other than workers).

4. A salary pay slip for private sector employees shall be submitted in accordance with a bank statement issued by one of the accredited banks in the country for a period of no less than six months. The profession shall be proved through a documented employment contract and a copy of the academic achievements.

Therefore, in case that the conditions apply to you, it is possible for you to bring your family. Apply for a visa at the immigration and residence department.