Hey. I usually play with 2 different mods (NPC Map Locations and Gift Taste Helper) that I got so used to them I often forget that I play with mods and these features aren´t in the normal game, so I wouldn´t wanna play without them if it's unnecessary. A friend of mine that just started playing Stardew Valley and with whom I wanna play Multiplayer with doesn't play with mods. My question is: If we play toghether and I use these mods, does it affect the game in any way or is the only difference that I have these features and my friend does not?
Those two particular mods should work fine for you in multiplayer and won't affect your friend. Most mods are this way, but things like custom maps would definitely cause issues if the other player doesn't have the same mod installed.