Hello. Indah is from Indonesian and Melayu origin. It has various meanings like “beautiful”, “lovely”, “magnificent”, “fine”, “fancy”, etc.
The use of meaning depends on what object you will describe it. Like:
“That dress looks beautiful”
“What a lovely day”
“What a magnificent scenery” Etc.
We usually use “Indah” for describing that phrase. And that name is usually for a girl and have general meaning. So all people can use it.
I’m an Indonesian. And I hope it helped you.