Do I need Curse Client for Minecraft mods?

I want to start modding my Minecraft, but do I need that Curse Client app so do it successfully or is that for something else?

Depends on the mod, you usually need forge. When downloaded, forge can be added as a profile option on the normal launcher (unless it's changed since i last used it!) then add zipped files to the mod folder in your.minecraft in roaming (accessed by typing %appdata% in start). I suggest getting minecraft magic launcher, it makes adding mods so much easier c