Yes, STEL Order, allows you to set a currency as the main currency for the company, the prices of the catalog products or services will always be displayed in the company currency, as will the reports, however, you can assign a currency directly in the customer tab.
Set a currency as the main currency for the company.
Go to the customer tab, Commercial > "Currency" tab, so that when creating documents for that customer it will show the currency that they have on their tab.
You can also make the currency change directly within the document in the More information > "Currency" tab and next to it the "Currency rate" field.
The program takes the exchange rate based on the exchange rate of the day according to the European Central Bank, but you can modify the exchange rate at the moment according to the one you need to indicate.