The requirements for you and your korean colleague are almost same, the only difference is that you need to provide the Korean residence permit or work permit besides other requirements provided by your colleague:
(1) An original copy of passport with enough blank visa pages, valid for at least another 6 months.

(2) A fully completed copy of Visa Application Form signed by the actual applicant;

(3) One recent 22(in.)-sized color passport photo, white in background, with a full front view of the applicant's head and shoulders but without any head cover.

(4)round-trip flight tickets and hotel reservation. Sometimes, the hotel reservation is not required