How can i get any data format and apply?

Well, just find the specification like i did for my BMP loader. Wikipedia often has a good explanation or at least a source link to a specification.

Every dataformat is different, so there's no general approach to this. Unity supports out-of-the-box JPEG and PNG which are the most common formats.

Note that writing an importer yourself for every major format is not easy and takes a lot of time. It might be easier to search for a paid solution. For example for the windows target platform there is the DevIL library which seems to be part of the TriLib asset in the AssetStore. This packet seems to be very cheap for what it provides. I did not buy, develop or test this package. I'm just judging from what it provides and how much time it would take to implement all that yourself.