Will my portal work properly on a mobile phone, or is it really made for people sitting at a computer?

Yes, it works on a phone, and that matters because a large share of the people who search on a travel website now do it from a mobile. The pages adjust to the size of the screen, so the search box, the results list and the payment page stay usable on a small display without the customer having to pinch and zoom. This is part of the normal portal, not a separate mobile site you have to buy or look after on the side.

There are honest limits. A small screen means long flight results with lots of filters, and hotel pages with lots of photos, take more scrolling than they would on a desktop. Card payment on a mobile also depends on your payment gateway and on the customer's own bank, because the verification step hands the customer over to the bank's page, and how that page behaves on a phone is the bank's doing, not ours. If a payment keeps failing only on mobile, that is usually where the problem sits.

It is also worth being clear that this is a mobile website, not an app. Your customers open it in the browser on their phone, so there is nothing to download and nothing for them to keep updated. If you want a real app with your icon on the customer's home screen, that is separate work and depends on your plan, so please ask before you promise it to a customer.

The quickest check is to open your own site on your phone, run a search you would actually sell, and carry it all the way to the payment page. If anything looks cramped or a button is hard to press, tell your support contact which page and which phone, and it can be looked at.