Once you have left to a foreign country, you must also have strong, valid and verifiable reasons to return to your origin country. One of these documents must be provided by you:
Proof of employment
Proof of pursuing academics
Proof of employment offer
One of the main reasons for visas to be denied is the inability of the applicant to guarantee to the embassy or consulate of the foreign country the applicant's ties to the origin country.
This leaves room for doubt that the applicant might overstay the visa period thus becoming an illegal immigrant in the foreign country. Illegal immigrants are detrimental to foreign country's economy and job opportunities. Hence it is important to prove that that applicant will in any circumstance return back to origin country on the expiry of the granted visa