To renew a residency visa in Dubai, one needs to submit a renewal application along with the necessary documents to the General Directorate of Residency and Foreigners Affairs (GDRFA) through their online portal or in person at one of their offices. Required documents typically include a valid passport, a copy of the current residency visa, a passport-sized photo, and proof of financial support. The renewal fee varies depending on the type of permit and the duration of the extension.