In English, a hera may be referred to as a spatula, a spreader, or even a squeegee. 
 
There are a variety of styles. I prefer the type shown above, called a debabera. The handle and the curve make it much easier for me to see what the paste is doing as I spread it across the stencil. In a pinch, a silkscreen squeegee pay be used instead, or even an old credit card. 
 
The largest one I sell is most often used to apply the paste when preparing a pasteboard. These are no longer being manufactured.