From the Overview: "The Islamic Republic of Pakistan is a parliamentary democracy in which the prime minister is head of government and the president is head of state. A bicameral parliament is comprised of a 342-seat National Assembly (NA) and a 104-seat Senate, both with directly elected representatives from each of the country's four provinces (Balochistan, Khyber Pakhtunkhwa or KPk, Punjab, and Sindh), as well as from the Federally Administered Tribal Areas and the Islamabad Capital Territory (the quasi-independent regions of Azad Kashmir and Gilgit-Baltistan have no representation). The NA reserves 60 seats for women and 10 seats for religious minorities on a proportional basis, meaning only 272 districts elect representatives. The prime minister is elected to an indeterminate term by the NA. The president is elected to a five-year term by an Electoral College comprised of both chambers of Parliament, as well as members of each of the country's four provincial assemblies. NA and provincial assembly members are elected to five-year terms. Senate terms are six years, with elections every three years. Senate powers are limited, and only the NA can approve budget and finance bills."
CRS In Focus, IF10359
Congressional Research Service: https://crsreports.congress.gov/