All bishops are appointed by the pope. The pope may select anyone he chooses. However, there is a process established in the Catholic Church that results in recommending a list of candidates to be presented to the pope for appointment.
The first step in the process is for bishops to recommend to the archbishop the names of priests from their provinces that they believe will make suitable bishops. The archbishop gathers the names of the recommended priests and distributes the list to the bishops under his direction. A province meeting is held, usually annually, where the bishops meet and vote on which priests to recommend. The number of priests recommended varies. The archbishop forwards the vote tally, the meeting minutes and the list of recommended priests to the apostolic nuncio. The apostolic nuncio gathers facts and information about the potential candidates. Based upon the information, he makes his recommendation for bishop candidates to the prefect. The prefect is the person in charge of the congregation of bishops. The prefect reviews and makes his recommendation of bishop candidates to the congregation of bishops who may or may not accept the prefect's recommendations. The congregation of bishops votes and the prefect meets with the pope and presents the final list of candidates. The pope reviews and decides which candidates will be appointed as bishops.