How to make the camera project a map in maya

The easiest way is the upper left corner.

Click this icon.

Pop up a window for importing pictures, and then import the pictures you want at will. If you don't want to see this picture, click it again and turn it off. It must be noted that the sizes of the four view windows must be the same when importing, otherwise the images will be displayed inconsistently in the four views, that is, when MAYA is just opened, or click the home button of the VIEWCUBE respectively. Is that what you mean? You don't use the plane once and import it once, but that's what camera projection should mean, isn't it?