The operation method is as follows:

1. Open WPSofficeapp on your mobile phone.

2. Click the red circle and white cross in the lower right corner.

3. Pop-up menu function, select text.

4. Click Create New Blank.

5. Click the small square icon in the upper left corner of the input method.

6. Find the brush and click Signature.

7. Add your name on the signature page and click Finish.

8. Click Insert to Document to display the signature in the document.