In the upper left corner of the window, click on "wps Form", and don't click on the small triangle next to it, because the content in the small triangle is different from that in the "WPS Form".
Find "File Information-File Encryption" and click it in turn, as shown in the figure below.
In the place shown below, press the delete key to clear the password in the box, and click OK to clear the password.
Click OK to save the wps document and cancel the password of the wps document.