Can I sell travel insurance or visa help on my portal as well as flights and hotels?

Yes, in most cases you can, though how it works depends on what you want to add and who supplies it. Travel insurance is usually offered through a partner who gives you a way to quote and issue a policy, and your portal can show it as an option on the checkout page so the customer ticks it before they pay. Visa help is different, because a visa is paperwork rather than something a supplier can confirm in seconds, so it is normally sold as a service you fulfil yourself after the booking is made.

For anything you handle yourself, the usual approach is to set it up as your own add on, with your own name for it, your own price and your own short description. The customer picks it while booking, it appears on the same invoice as the flight or the hotel, and you get a job to follow up on. That keeps the whole trip in one record instead of you chasing it in a separate notebook or spreadsheet.

There are honest limits worth knowing. Selling insurance is regulated in many countries, so you may need a licence of your own or you may have to sell through a licensed partner, and that is a rule from your regulator, not something the software can decide for you. If you want a live insurance price that changes with the trip and the traveller age rather than a flat fee you set, that needs an insurer who offers an API, and not every insurer in every market has one.

The sensible next step is to decide whether you want to fulfil these yourself or through a partner, then check what add on products your plan allows and whether the insurer you have in mind can be connected.