Under the Pakistani Law, court marriage with a christian can be contracted. A muslim male can contract court marriage with a christian female. If both the male and female are Pakistani Nationals, then the girl should be at least 16 years old while the guy should be at least 18 years old.
If the girl is foreign national, the marriage can still be contracted. A foreign national should bring original password at the time of marriage and provide the required copies accordingly.
Muslims can be witnesses in the court marriage of a christian. If the christian wife like to convert to islam then she can be converted before the marriage. However, in that case an accreditation from qualified institute/mosque is required in that case.
For more on court marriage you can contact firstname.lastname@example.org or call +92-3123450006