What’s the best way to tell a user that the field is a textbox?

The situation:
I have to tell the user that those fields are actually a textbox and they have to enter something in that, the one before the red square (amount) is readonly and can't be changed. I need a smart way to differentiate those fields.

Also you probably can notice that this view is divided in 3 sections after the HR tag. Those are dropdowns and it's not clear that they contains something. In another view I added an icon on the left like this:


I think they needs more than an icon or it's good enough like this?

Have some suggestions?

NB: I can do whatever i want with the css and I don't have any limitations. Also the project has font-awesome and ionic icons installed. I'm using the ionic framework.