To password-protect PDFs (the recipient must provide the password in order to open it), go to the company's settings to the Miscellaneous tab:
Check the box Protect PDFs with a password.
From this moment on, you can assign passwords to employees in tab 10 of the employee management:
If you click on Generate, it will generate a random password consisting of numbers, upper and lower case,
It is also possible to type something. It lets you (or the employee) choose the password.