On the Freecash App
Click the 3 lines on the left of the navigation bar at the bottom of the screen and from here you can select the language you want to display Freecash in.
On the Freecash Website
Scroll to the bottom of the Freecash Website, you will see a language option with a flag, if you click on that, it will allow you to choose a different language to display the website in.
You can display Freecash in the following Languages:
English
Japanese
German
Italian
Spanish
Swedish
French
Polish
Turkish
Portuguese
Danish
Dutch
Korean
Please note that while you can change the language that Freecash is shown in you cannot change your country. Using a VPN could lead to a ban on your account.