How to fill the pen in PS to detect the color of the image?

An image dug with a pen needs to be converted into a selection before it can be filled with color.

1. Drag the image to be processed to ps, click the Pen Tool button on the toolbar on the left side of ps, and then select the image to be keyed:

2. Press and hold the "Ctrl" key and the "Enter" key on the keyboard at the same time to convert the path into a selection, then press and hold the "Shift" key and the "F5" key at the same time to open the fill panel and select the content item as "Color ...":

3. Select the color to fill in the pop-up color picker, and then click OK, and then click OK in the Fill panel:

4. At this point, the image selected by the pen is filled with the color you want to fill: