If you’ve got the password for your payslip PDF, you can open the file, enter the password and save or print it as a new PDF if your employer allows. This is fine if you have one document but can be time consuming if you have several password protected payslips.
I was also in the same situation when I was organizing salary records, so I used Softaken Unlock PDF Files. After entering the right password it unlocked the security on my authorized PDF files without disturbing the original formatting. It also read multiple PDFs at once, which saved a lot of time. The tool will let you remove restrictions on editing, copying and printing, but it does not crack unknown passwords, so you will still need the right password for protected files. If the PDFs are ones you have or have permission to use, this is a practical option.