Canon PIXMA MG6320 Online Manual page 253

Standard
It is recommended that you normally select this setting.
High
Compresses the file size when saving. You can reduce the load on your network/server.
Important
PDF images may degrade if you repeatedly save them with high compression.
Security
You can set passwords for the created PDF files.
Select Password-protected to display the Password Security Settings dialog box in which you can
set a password to open a file and restriction on functions such as editing and printing.
Password Security Settings Dialog Box
Related Topic
Save Dialog Box (Create/Edit PDF File View)