Minecraft does not show a mod option?

I wanted to install again after a long time a mod. Now I've seen that you can just twitch via twitch and then you can start directly, but if I open Minecraft wid I nowhere a mod option displayed, which should ever be directly in the start screen next to 'Realms', someone knows what that can lie? : /

The mods button is only for an overview of installed mods. It is a feature of Forge.