A corporation key is a password given to you by the Canada Revenue Agency (CRA). You use it to access the Online Filing Centre. It is not the same as a corporation number that the CRA also gives you. When you use your corporation number with the corporation key, you can access online transactions with the CRA. These transactions include adding or changing your corporate address, dissolving your corporation, filing proxy circulars, filing financial statements, and even managing email subscription reminders. Best of all, these online transactions do not require a fee. There’s also no fee associated with requesting a corporation key.When you register online to obtain a corporation key, you have to confirm your address as registered with Corporations Canada. The key is then mailed to your company’s registered office address. As a control measure, only share the key with those who can file a return on your behalf.If you misplace or lose your corporation key, don’t fret. You can also find it in the acknowledgement of receipt you receive when you file your corporation’s most recent annual return. If for some reason you can’t access this file, gain access by going to the Obtain Corporation Key web page. The utility can do a reverse look-up based on your business number or corporation name plus your corporation number. If you request a new corporation key, the old key becomes invalid immediately. The new corporation key can only be sent to the current registered office address.