Where can I find launchpad?

The Launchpad icon looks like one of these- it changed with Big Sur. It should be on your Dock-

You can also get to it with the finger gesture, by pulling your thumb and three forefingers together-

Hope that helped!

In Big Sur and Monterey it's at the bottom of your screen in that long "bar" of icons. It's the one with 9 small squares of various colors.

What OS are you using?

IIRC earlier versions had a small retro rocket ship icon