Do inbound faxes use my plan's minutes?
Faxes use the minutes allotted to you in your monthly plan. So if your plan charges per minute, then the amount of time it takes to receive a fax would be calculated in your monthly cost. If you are not charged per minute, then your faxes would be covered and you would not be charged to receive them.
The duration of each received message can be found in your call history reports.