i cant add mods !!! help me

[ller25612082]

when I try to add mods in app data technic launcher and  mods folder when I add mods in mods folder and then when I launch it it crashes all the time

[Curunir]

This means that you can add mods fine, you are just crashing your game because you have no clue what you are actually doing.

If you change anything about your Tekkit installation, it automatically becomes a custom modpack, which is not supported as a Tekkit installation. Head over to Platform Pagoda and look around for guides on how to modpack. It's not rocket science, but it's not entirely trivial, either.