I've been creating for 6 years and adding new assets every couple of days. There are several technic to make them. You need a computer indeed but some creation methods don't require a camera. You can generate textures procedurally using software.
Let's say I want to "texturize" an existing brick wall of a building.
I make high-quality photos, but then what? How do I create bump maps and so on? Do I need a stereoscopic setup? Do I need polarizing filters or something like that? What software is used?
IF you want to make it high-quality, there is a technic called photogrammetry. You need to take hundreds of photos under same light, without shadow or reflection. Then you create the 3D model of the facade using photogrammetry software like metashape or realitycapture. After you have the 3D model, you need to transfer 3D data to 2D texture. It's called baking. After baking is done you endup with basecolor(diffuse/color), height(displacement), normal and ao(ambient occlusion) maps.
If you are looking for a basic way, just take one clean photo(without visible shadows or reflections) There is method called Bitmap to material. Basically, you grayscale your image and using that grayscale data to create other maps like bump, roughness height etc. If you've experience in that area you can make them in Photoshop. Adobe Substance Sample(Substance Alchemist) has great abilities to generate using that method + AI.
To clear reflections you need circular polarization filters. You can also use cross-polarization method to clear all unwanted reflections. But It require addinational light source and linear polarization filter.
Texturelab is also pretty decent for a node-based texture design software. (also Free) Only issue is it hasn't been update much, yet relatively feature complete. https://www.texturelab.io/
Most can guess the paralax, bump maps, ect...
Example using the above methods (took longer to upload than make)
