yeni gta 5 aldık arkadaşımla online' da araba mod'u ile oynayabilirmiyiz ?
This isn't site-related so you might have wanted to post your question in this section. Also this isn't a Turkish forum, but an English-speaking one, so you might want to have asked the question in English.
To answer the question - You can't play with mods in GTA:Online. There are alternative multiplayers like FiveM, which do support server-sided mods. These alternatives are in no way related to GTA:Online nor Rockstar Games.