Can my customers see prices in our local currency even if the supplier gives the rates in dollars?

Yes, in most setups your website can show prices in your local currency even when the supplier quotes in another currency. The system takes the rate it receives, converts it using the exchange rate loaded into your portal, and shows your customer a figure in the currency you have chosen as your display currency. Many portals also let the customer switch between a few currencies themselves, so a visitor from abroad can see something familiar.

The exchange rate used is not something we invent on the spot. It comes from a rate source that is refreshed on a regular schedule, so it will be close to the market rate but not identical to it at every second of the day. Because of that, most agencies add a small conversion margin on top so that a movement in the rate between search and payment does not eat into their earnings. Whether you can set that margin yourself, and how finely you can control it per supplier, depends on your plan and on how your portal is configured.

It is worth remembering that what your customer pays and what the supplier bills you can sit in two different currencies. Your payment gateway has to accept the currency you are displaying, and your supplier will usually still settle with you in the currency of their original contract. This matters most on refunds, because a cancellation processed weeks later may convert at a slightly different rate than the booking did. Your reports can show both the sale currency and the supplier currency so you can see where the difference came from.

Before you go live, check which currencies your suppliers quote in, confirm your payment provider accepts the currency you want to sell in, and decide what conversion margin you are comfortable with.