That process varies greatly depending on which game engine you're talking about. We've got some members who may be able to help you figure it out if you're talking about translating HTML, Ren'Py, RPG Maker, QSP, and even Unity games.
It would be awesome if you could even name the game since someone may have already done it and could send you a file you can translate then they could teach you how to do that and add your translation to the game.
That process varies greatly depending on which game engine you're talking about. We've got some members who may be able to help you figure it out if you're talking about translating HTML, Ren'Py, RPG Maker, QSP, and even Unity games.
It would be awesome if you could even name the game since someone may have already done it and could send you a file you can translate then they could teach you how to do that and add your translation to the game.