Setting up Multicurrency in an existing file
You are able to turn on the Multicurrency option at any point. However, if you start recording transactions without setting up Multicurrency, all transactions for customers, vendors and salespeople will be set up to use the home currency as the currency in which you conduct business with them. Once the currency has been selected it can’t be changed. If you wish to begin using a different currency for these individuals, you'll need to create a new customer, vendor or employee card for each of them. This is necessary to ensure that historical amounts for these individuals aren't misstated.
If you're unsure about when to start using Multicurrency, you probably should consult your accountant or a Certified Consultant.
More information about the Multicurrency feature can be found in the help files: