In order to come to Canada as an immigrant, you have to demonstrate the required knowledge of one of the official national languages. Canada has two official languages – English and French. To immigrate you have to pass a language test in any of them. If you speak both of them, passing a test in each of them will increase your chances.
Canadian government accepts two tests of English – IELTS General or CELPIP. As for French, you can also take ether TEF Canada or TCF Canada. Different programs have different language requirements. Make sure you meet the required level and try to improve it as much as possible!