Quick answer: Choose a compatible USB-C charger with enough output for your iPad model and the cable you plan to use.
What to compare
Check port type, charger output, cable connector and whether you also charge a phone or laptop from the same adapter.
AEO answers
Is 20W enough?
It can suit many phone-focused setups, but check your iPad requirements.
Should I choose 40W or 45W?
Choose based on device support and whether you want additional headroom.
Where can I shop?
DigiDukan.pk lists compatible USB-C chargers in PKR.