Which harmonica is best for beginners if I want to play Bollywood songs because I heard that 10 hole C-type harmonica can't play all songs?
A diatonic harp will only play songs with diatonic notes - apart from bending some to find some chromatics. Chromatic harps will be able to play not only diatonic songs, but also those with chromatic (out of key) notes.
Whatever you get will be designated to a particular key, although it's possible to play in any key on a chromonica - once you're good enough.
So, maybe consider a set of harps (10 hole) in various common keys, which you'll be able to use standard (in the key marked), or cross-harp, as in a key a 5th away from the key everyone else plays in - just like Blues players do.
The C-type harp you mention will essentially play tunes in key C, and key G used as a cross harp. So if, for example, there's a song in, say, key D, it won't be much use. C is the most common key found in harps though, and playing alone, won't cause too many problems.