Finance tab (Vendor invoice)
In this tab, you can:
check the Exchange Rate between the base system currency and the currency used in the vendor's invoice.
enter the Date on which the exchange rate was updated if you have changed it manually in the Configuration menu > System Values: Advanced > Currencies.
check after which action the rate was updated in the Exchange Rate Update When section.
To find out more about exchange rate updates, see the Exchange Rate Configuration article.