Where travel gets in the way
Abroad, texts to your home number can arrive late or cost roaming fees. Some local apps also refuse any country code but their own.
The dashboard opens on any Wi-Fi connection, so you read the code on screen whatever SIM is in your phone.
Which country to pick
A number from the country you're staying in works best. Choose the app first under Get a number and the countries that accept it are listed from the lowest price.
Prices depend on the app and the country. You see the amount up front, and it leaves your balance once the number is issued.
No code, or needed again
Wait 25 minutes without a code and the price is credited back to your balance. Try a neighboring country's number next.
If you'll log in to the same app several times during the trip, a rental number is easier. Rent it for a period that covers your dates.