A former SF Giants first-round pick is now free to join any team. According to the team's transaction log, Hunter Bishop was among the minor leaguers to elect free agency.
Former first-round pick among flurry of SF Giants minor leaguers to elect free agency
Elect is the term baseball uses, but it is not a discretionary decision. It simply means that a player's contract has expired.
If a player has six years of minor league service time and they are not on the 40-man roster, then they are eligible for free agency. This is true for any player drafted in the 2019 draft class.