It starts with an inspection to locate entry points, runways and nests. That decides the mix of traps, cages and registered rodenticide baits, placed out of reach of children and pets.
The job doesn't end with the catch: maintenance means sealing entry points and checking control points regularly so new rodents can't get in. That's why businesses usually book it as scheduled visits.
If you also see opossums on your premises, mention it in your request: they are handled with cages, not bait.