Hi sani,
PPR is an abbreviation of Pass-port Request. Basically when your application reached at the stage when visa is needs to be issued, visa office asks an applicant for their passport. Passport request is normally made in two steps. In 1st step (which usually called by people and known as PPR1) visa office asks an applicant to provide their passport copies and any updated information. Once you submit 1st part (PPR1) to visa office, they review your information and after review they send you final letter in 2nd step which is called PPR 2. In this final PPR2 letter visa office asks an applicant to send their passports to visa office.
Hope this information helps you.
Best Regar,
Mian Noman Tariq