PS's filling tool is in the drop-down option of menu bar editing. When the fill tool does not open a file or create a new canvas, it is in a gray inoperable state. The specific method to find the filling tool in PS is as follows:

1. Open the PS software in the computer and click the Edit button in the menu bar at the top of the page.

2. At this point, you can see that the fill tool is in a gray state in the expanded options.

3. If you click the Edit button again in the open picture, you can see the Fill button in the expanded options, and then click it.

4. Click the drop-down arrow used in the pop-up fill dialog box, select the desired fill color, and then click OK.

In this page, you can see that the current picture has been filled with foreground color.