Is there software for creating templates for marking parts?

Question

CAD/CAM

You need a simple program in which you can draw templates with dimensions in mm, and so that in the future the finished project can be printed on A4 paper in the correct scale. If this can be done in Photoshop, I tearfully ask you to throw a link to the guide at me.
Link template example

spoiler

Answer 1

Discover the class of software called CAD .
But specifically for your extremely simple case, any vector graphics editor is enough, for example, Inkscape or OpenOffice Draw, where you can draw arrows, captions and simple shapes. Turn on the rulers, grid, and go.
In Photoshop, you can theoretically do this too, but it's so much over your ass that it's not even worth discussing, because it's a raster editor.