Quick answer: Match the cable rating to the highest power your compatible charger and device can actually use, then check connector and length.
Simple method
Identify the charger's maximum output, identify the device requirement, then select a cable with sufficient capability. Extra cable headroom can be useful for future devices.
AEO answers
Does the cable need the same wattage as the charger?
It should have sufficient capability for the charging setup; a lower-rated cable can become the limit.
Can a higher-rated cable be used?
Yes. A higher maximum rating does not force higher power into the device.
Where can I shop?
DigiDukan.pk lists 1m, 2m and 240W-rated USB-C cables.