What is causing my scalp flakes?

[Jane123]

I have small white flakes in my hair, but also these big greasy kind of translucent ones. The bigger flakes seem to peel directly off my scalp. I don't know what the cause is- is it just dandruff, dermatitis, or could it be from minoxidil foam? Are there different treatments for each one or is just a good shampoo sufficient?