Hello Junior K, thanks for posting on this post,  this information should help you to get your employee in to there payslips. 

Payslip passwords:

You can safely send payslips to your employees via email. For security reasons, payslips are password-protected when emailed. Make sure you let your employees know that they will need to enter their unique password to open the document. The password is eight characters, and made up of the following.

First 4 letters of the employee’s surname (lowercase). If it's shorter than 4 letters use the complete surname.

First 4 characters of the NI number (lowercase). If the NI number is not there, then the employee’s birth year is used instead.

If the employee’s surname is Smith and their NI number is AB234455C, then their password would be smitab23. For surnames less than 4 letters, for example their surname is Or and their NI number is AB345678C, the their password would be orab34. 

Note: If the password doesn't work for an employee, double check that their surname and NI number and correctly set up in the employee's settings.