TempNumber offers numbers from 25+ countries. Badoo is global, so US, UK, and European numbers all work well.
Open Badoo and tap "Sign Up". Choose your country code and enter the temporary phone number.
Badoo will send a 5 or 6-digit code. Open the TempNumber inbox and copy the code.
Submit the code in Badoo. Upload photos and fill in your profile to start connecting globally.