A Shopify account can be connected to Brightpearl even if they do not share the same base currency. For example, Brightpearl can be set to use GBP as the base currency and all the accounting, but Shopify can be using USD as the default currency. In this case your orders will download into Brightpearl using the Shopify currency (USD). Brightpearl will then use the exchange rate provided by Shopify to display the order base currency total and post the invoice accounting.
Payments will also download into Brightpearl, marking the order as paid. Note that the accounting entries made for the sales receipt will be created in the Brightpearl base currency. This is done by directly converting the order total using the Shopify exchange rate (this is not how multi-currency conversions are done for foreign currency sales made directly within Brightpearl). This can lead to a penny difference between the invoiced amount and the paid amount. To correct these penny discrepancies you can edit the sales receipt journal to post the correct values.
In Shopify, multiple currencies can be created so that prices can be converted and displayed online in different currencies. However, any orders received through your site are always shown in Shopify using the default currency. In this case all your orders will continue to download into Brightpearl using the default Shopify currency, even if Brightpearl is using a different base currency.
If the currency doesn't exist in Brightpearl, the order will not be downloaded. You will need to create the currency in Brightpearl to ensure future orders download. Any orders which failed to download will need to be manually entered into Brightpearl.