To add a new courier or courier service, simply navigate to Shipping > Couriers
Overall courier does not yet exist
If the courier does not exist for the new service you want to add - first you will need to add the courier
Only the courier name is mandatory but you can enter additional optional contact info.
Overall Courier already exists
If the overall courier already exists for the service you want to add - now click Manage Courier Services on the relevant courier:
Then add the courier service name, tracking URL (if known) and a fuel charge if applicable (enter 0 if it does not apply)
Once you have added a courier service it is advisable to setup courier pricing for the service, see guide here: