GVWR is printed on the certification label, usually on the driver door jamb. It is a rating, not the weight on the scale. Regulations use it to decide who needs a CDL, who needs a USDOT number and which rules apply to a truck.
A commercial driver’s license is required for a single vehicle with a GVWR of 26,001 pounds or more. A USDOT number is required for most interstate commercial vehicles with a GVWR of 10,001 pounds or more.
Regulation: 49 CFR 383.5 and 390.5.