English and French are Canada's two official languages. The ability to communicate (speak, read, write, and understand) in English and/or French is extremely important if one is to become well established in Canada.
Immigration programs such as the Skilled Worker program and many others require a certain level of English and/or French.
The best way to provide evidence of your language ability is to take a language proficiency test given by an organization that is approved by Citizenship & Immigration Canada.
You may arrange to take a language test from any of the organizations listed below.