476 visa cannot be extended. But there are pathways to extend your stay, such as applying for a new visa or enrolling in a part-time course. Some of the visas you can apply for are visa subclass 186 (if your employer nominates you), visa subclass 189 (Skilled Independent visa), visa subclass 190 (if an Australian state or territory nominates you, and visa subclass 489 (if you are living in regional area of Australia).