The safest source is the or "Umm-ul-Qura Publications" official websites. They sometimes offer a "Sample PDF" of the updated version for verification.
If you own the physical book, sharing for personal/non-commercial educational use is generally acceptable, but commercial distribution is not. muallim ul quran dr ubaid pdf upd
If you are unable to locate the PDF at all, let me know and I can guide you to specific library catalogs or suggest alternative, similarly structured Quranic Urdu textbooks that are openly available. The safest source is the or "Umm-ul-Qura Publications"