Can I book a flight with stops in more than one city for a customer on one ticket?

Yes, in most cases you can book a multi city trip as a single booking, although how far you can go with it depends on which airlines and suppliers are connected to your account.

A multi city search lets you enter each leg separately, so a customer who flies out to one city, continues to a second and comes home from a third is priced as one journey instead of three unrelated bookings. Full service airlines reached through global distribution content usually handle this well, and the combined fare often works out better than buying each leg on its own. You also get one booking reference and one ticket, which makes the trip much easier for you to manage if something has to change.

There are honest limits. Low cost airlines normally sell one direction at a time, so if a leg sits with one of those it has to be issued as its own separate booking with its own rules and its own baggage allowance. Mixing two carriers that have no agreement with each other can force separate tickets too, which matters because a delay on the first leg is then not the second airline's responsibility. Some suppliers also cap how many legs one search can contain, and very unusual routings may still need a manual quote.

Before you promise a multi city itinerary to a customer, run a test search on your own portal using the kind of routing your clients ask for most, and check whether the result comes back as one booking reference or several, because that tells you how changes and refunds will behave later.