Thanks for reaching out to TextNow Wireless support. You will need to add the country code, however we have simplified the process.
From the TextNow dial pad there will be a small drop down menu on the upper right labeled by default USA and Canada. Click it and it will prompt you with all the available country codes you can choose. When one is selected it will auto populate the number field with the country code.
Let us know if you have any questions or concerns.