How do you obtain a new pistol in GTA Online?

To obtain a new pistol in GTA Online, one typically needs to visit Ammu-Nation, the game's weapon store found at multiple locations across the map. Once there, browse through their selection and purchase the desired pistol, provided that it is unlocked and he has enough in-game currency to afford it. Certain pistols might require the player to reach a specific level before becoming available for purchase. Additionally, special or exclusive pistols may be obtained through completing specific missions, activities, or during certain events. After purchasing, the pistol is added to his inventory and can be customized with various upgrades such as scopes, suppressors, and extended magazines if they so choose.