Your host university may require you to present a certificate of documented language skills. The IC Administrator will provide you with a document called Proof of English proficiency once you have been accepted to an International Campus exchange. This is generally enough evidence of your language skills.
In rare cases, you may be required to complete a language test, to prove your English level. Please see the information in Intapps to check if you need a TOEFL test or other English requirements for the application to the university you are interested in.