Permit requirements vary by jurisdiction, duration, use, utilities and occupancy; buyers should confirm the local path before delivery rather than treating a temporary unit as automatically exempt.
The use and location usually determine the review path
A construction office, classroom, retail office and public-facing trailer may be reviewed differently. The jurisdiction may consider zoning, building, electrical, plumbing, fire access, accessibility and the length of placement.
Compare the same office and site scope.
Give every supplier the real ZIP, use, size range, term, delivery date and setup responsibilities.
Assign permit work to a named party
Do not assume the supplier, general contractor or property owner will handle approvals. The proposal should identify who prepares drawings, files applications, answers corrections, schedules inspections and pays fees.
Keep approval dates tied to the delivery schedule
A trailer can be available while the property is not ready to receive it. Build permitting, site work, utility release and inspection milestones into the schedule used for mobile office supplier quotes.
Turn this answer into a useful supplier comparison
Record the decision that applies to the property, who owns it and when it must be complete. Connect that note to the proposed unit, delivery plan, access equipment, utilities, service and removal so an unanswered assumption does not return later as a change in price or schedule.