As you describe this simple App, it seems you want an all-in-one solution. A major problem with all-in-one software solutions is that they are rarely simple, and also rarely have all the options the majority of users would need. If the software did have all of this, it would not be simple.
It sounds like your description is a Surface computer.
My Surface Book is loaded with very good photo editing and communication software. But when I want to do as you describe, I use my Surface to do this:
"Allow me to take the photo ..."
Take a photo with the Camera app. Then choose item "Open folder". Windows file manager will show it as the newest item.
"... mark it up and save it …"
Right-click on the newest item, and "Open with" Paint. When finished marking up, close Paint, using option "Save".
"... email it."
You are back in Windows file manager again. Right-click on the photo and "Share …".
Or drag the marked up photo to your email app.
I hope this is helpful.
