Use an unlocked phone that supports eSIM. Check your exact model and region of purchase with its manufacturer. You need one eSIM for each phone.
Check when your selected plan starts before installing. After payment and delivery, open your private order or installation email and install over Wi-Fi. At your destination, select the travel eSIM for mobile data and enable its data roaming. Follow the plan’s activation instructions.
Activation varies by plan: some start when installed, while others start on the first supported network connection. Check the activation rule and installation window in your selected plan.