If you do the experiment with a sufficiently bright, visible light source, then the "screen" could just be a sheet of white paper that you look at with your eyes to see the projection of the interference pattern.
The screen could instead be a sheet of photographic film that you expose in the apparatus, and then develop afterward to reveal the pattern. The screen could be a CCD image sensor. It could even be a single photo diode that is mechanically scanned through the stationary interference pattern. The screen could be literally any technology that you would use to map the intensity of the light that is projected through the slits.
I do not know what they use to detect electrons or other particles for which the double-slit experiment has been performed, but the principle is the same. It's anything that can map out how many particles "arrive" at different locations in space.