Can you clarify what you want to do?
Draw a fullscreen quad?
Check out https://github.com/UncleThomy/BloomFilter-for-Monogame-and-XNA
There is a quadrenderer, which generates a quad and supplemental basic vertex shaders/pixel shaders. The whole setup of the sample is really simple I think, so it’s easy to understand i hope.
Otherwise you can check out https://github.com/UncleThomy/DeferredEngine
or https://github.com/UncleThomy/Modelviewer
which uses fullscreenquads the same way, but has a few other shaders and is more complicated to understand.