When using WPS Office for mobile, we can set a password to protect a PDF document. 

The document receiver should enter a password before opening or editing the PDF.

1. Click the Tool button.

2. Go to the Edit tab.

3. Choose Set Password.

There are two types of protection: Enable Reading Protectionand Enable Editing Protection.

·ONE: Enable Reading Protection

Enter the password for reading protection. In this example, we set 'WPS' as the password. Then, click Confirm and exit the document.

* If we want to open the PDF again, a password is needed. Enter the password in the popup.Then we can read the PDF again.

· TWO:Enable Editing Protection.

Enter the protection password.Here we set it (protection password)  as 'wps'.

* When we return to the editing interface, the password is needed for editing the document. Enter the password,and we can edit on the PDF.

· How to remove the password

1. Return to the password setting interface.

2. Delete the password to cancel the protection.

* Note that you need to remember the password, or else the PDF will be locked.