If you want to learn how to use the undo button in photoshop, here are the easiest steps. This command will reverse the last action you took or will reapply an activity if you just reversed it. For instance, if you apply a brushstroke that you do not want there anymore, utilize Undo to eliminate that stroke. Then, if you quickly alter your mind, you can redo it by utilizing the command again.
Press the Undo/Redo shortcut keys in photoshop rapidly to toggle an effect on or remove an effect, an image, or text. When you determine which method to go, quit toggling. This treatment works best if you press Ctrl+ Z (Command+ Z on the Mac) to use both Undo as well as Renovate.
If you do anything else after you apply a command, and afterward change your mind regarding that command, you’ll have to turn to another fix-it technique. If you can’t undo or redesign an action, Undo/Redo will turn gray, revealing that it’s inaccessible. If the button is grey, the buffer is already empty.
Revert replaces your existing file with the last conserved variation of the data, effectively wiping out whatever you have already done since you last conserved the documents. You can change to the last variation of the file by selecting FileRevert.