Modding in Grand Theft Auto (GTA) is when people change or add things to the game that weren't originally there. It's like when you add stickers to your toy car or change the color of your toy gun.
In GTA, people can change the cars in the game, add new buildings, change how the characters look, and even add new missions or objectives to the game. It's kind of like having a whole new game to play with different rules and things to do.
But be careful, because not all mods are safe. Some mods can cause the game to break or not work properly, and others can even have viruses or harmful software in them. So it's important to only download mods from trusted sources, like official websites or well-known modding communities.
Also, it's important to remember that modding can change the way the game was meant to be played and may not be allowed by the developers of the game. So it's important to follow any rules or guidelines set by the game makers, and to always play safely and responsibly.