You can apply for family visit visa through Metrash2 application from mobile under visa service option. The documents you should required for wife will be marriage certificate and birth certificate for children attested from Qatar embassy in your country and passport copy front page.

While applying via Metrash2 application you need to upload the scan copy of attested documents and passport copy.

However please verify if your country is listed in the application.

Please note that it is up to the department of immigration to accept or reject any application.