Hi,
As per the CRA capital gains guide you need to report foreign exchange gains > $200 CAD on Schedule 3 under "Bonds, debentures, promissory note, and other similar properties. To do this in UFile you need to go to the interview setup section and check "Capital gains (or losses) and capital gain history". On the left-hand display click on "Capital gains (or losses) and ABIL, and select Bonds, debentures, promissory notes. Identify the currency under "Description of property" and convert the amount to Canadian dollars using the Bank of Canada web site or OANDA. You need to convert the amounts to CAD manually and enter your proceed and adjusted cost base accordingly. [note: I work for UFile]
Here's the link to the capital gains guide: https://www.canada.ca/en/revenue-agency/services/forms-publications/publications/t4037/capital-gains.html#P927_70485