Go to your Minecraft files. From there, go to the folder called "versions" and go into whichever version of blocks/items you are looking for (1.18.1 if you want to see the most recent version of textures). Extract the jar file located in whichever version you chose in with a file archiver program (7zip, WinRAR, etc.) With the folder that you just extracted, go to assets>minecraft>textures. There you will find the original texture files for whichever version you chose.
Hope this helps!
