It depends on the facility, but typically the requirements are less stringent. Many just require a disease screening and questionnaire about hobbies and whatnot. Once approved, men get paid per sample collected. Typically, clients will review details about donors and select from available samples.

For egg donation, women must first be approved by an agency, then selected by a client. Agencies commonly boast ~90% rejection rates as a selling point, then there's no guarantee that one will ever be selected by a client. Some women may be interviewed by multiple families and never get selected or compensated.