If you are applying for a Schengen visa to visiting friends or relatives living in the Schengen Area, there are some additional documents you need to attach in order to prove it such as:
1. The formal invitation by the relative/friend residing in a Schengen country.
2. If the applicant declares that he/she will be covering all the travel expenses, proof of one’s financial status is requested otherwise if the relative / friend is to cover the applicants’ expenses, a formal document issued by the competent authorities to a resident of a Schengen country (the friend / relative in this case) is to be submitted.
3. If the applicant will be covering the expenses on his/her own, the relatives / friend’s name, and copy the address of their passport will suffice. In case that the friend / relative is not a citizen of this Schengen country, the copy of the residency permit will also be required.