How to unlock characters from gta v in the online mode?

The provided source only describes the single‑player story of Grand Theft Auto V, detailing the three protagonists—Michael De Santa, Franklin Clinton, and Trevor Philips—and the open world setting. It does not include any information about character unlocks or progression in the online mode. Therefore, I cannot provide a method for unlocking characters in GTA V Online based on the evidence at hand. For guidance on online gameplay mechanics, you may need to consult official Rockstar documentation or community resources.