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Hello Mahmoud. Yes, you can make your own image textures so you can use as stencils in your brushes or make your own custom brushes, and on top of that there's addons that make even cooler stuffs. As you go forward you'll learn most of it, I suggest for now stick to the basics, since in Blender UI things can get very convoluted. 

You can make them in Photoshop or procedurally. If you want we could link you up to courses where things like that are used, but again, those are concepts that will feel a bit crazy right now. 

There are Image Textures in the Source Files, like the wall Texture Kent uses:

You can also find a lot of Textures for free at Poly Haven, https://polyhaven.com/