Family Reunion with “Flüchtlingseigenschaft”

Congratulations khalid.ahmadii this are very good news!
As a recognized refugee under the Geneva Refugee Convention, you can bring your immediate family, which includes your spouse and underaged, unmarried children, to Germany. In case you just received your positiv feedback - less than 3 months - you can apply for a so-called "privileged family reunification". With that you don't have to prove enough financial means or a minimum size of apartment. You can find all the information and requirements for family reunification as a refugee on our website, Handbook Germany.
So, if you are still within the first 3 months of your approval, you should apply at your local foreigners department to have advantages and your family can join under easier requirements. Alternatively, to make sure that you gave a timely notice within the first 3 months, you can also register your family at the website of "Auswärtige Amt" (German foreign office): https://fap.diplo.de/webportal/desktop/index.html#start This is very recommended due to the importance of the three months notice and the very long waiting list at the German embassy/consulates.
After your notice at the foreigners department or "Auswärtige Amt", your family needs to book an appointment btw. need to get on the waiting list at the embassy/consulate to apply for a visa. Since the embassy/consulates in Afghanistan are all closed, your family can apply at the German embassy in Teheran or in Islamabad. Your spouse and child should make sure that, among some other documents, they have a valid passport, tazkira, marriage and birth certificate (with translation and legalization).
Please note that there is no need to involve a lawyer with a status as a recognized refugee. However, you can reach out to the Refugee Law Clinic in Berlin. They also provide consultation for family reunion only.
Please let me know if something remains unclear or you have further questions.