To change the language of the mobile app, go to Profile ⟶ Settings ⟶ tap the flag in the upper right corner, and select your preferred language.

On the web, you'll always find the flag displayed in the upper left corner of your screen.

Please note that it's not possible to change the country your account was created in.

If you're logged out of the app or the web version, you can select a language and a country at the bottom of the login screen. However, be aware that if you don't have an account created in the country you select, instead of logging into your original account, you'll create a new one.