1. First, open the mobile phone WPS software and click the document, as shown in the figure below.
2. Enter the document and click Edit, as shown in the figure below.
3. Enter the editor and click the "Menu" icon, as shown in the figure below.
4. Enter the menu bar and click "Brush", as shown in the figure below.
5. In the pop-up window, click "Use Finger" to open the slider, as shown in the figure below.
6. Finally, sign by hand and click Finish, as shown in the figure below.