Yes! The Duolingo English Test is accepted as evidence of English proficiency for visa purposes in both the United States and Ireland. It depends on whatever technique you choose to apply in the UK and Canada. Traditional study permits call for proof of admission to a designated learning institution (DLI). It is possible that you will not be required to take any additional English examinations in order to get a study visa if the institution that you are applying to includes the Duolingo English Test as part of their application process.