The country section is pre-filled for you as the United States of America, as you are making a payment to the beneficiary - Flywire Payments Corporation. Flywire is headquartered in Boston, USA, thus you can also see our address listed on the form.
Please be assured that the funds will be received by Flywire, and processed in the destination currency and sent to your stated institution regardless of its country e.g. Canada/ United Kingdom.