Some visas can be granted on arrival or by prior application at the countrys embassy or consulate, or through a private visa service specialist who is specialized in the issuance of international travel documents. These agencies are authorized by the foreign authority, embassy, or consulate to represent international travelers who are unable or unwilling to travel to the embassy and apply in person. Private visa and passport services collect an additional fee for verifying customer applications, supporting documents, and submitting them to the appropriate authority. If there is no embassy or consulate in ones home country, then one would have to travel to a third country or apply by post and try to get a visa issued there. The need or absence of need of a visa generally depends on the citizenship of the applicant, the intended duration of the stay, and the activities that the applicant may wish to undertake in the country he visits; these may delineate different formal categories of visas, with different issue conditions.