No, it is not necessary to have a CRA My Account to do your taxes and file them. It is recommended that your wife set up her MyCRA account, to be able to access her tax return and credits given by the government if any, and other aspects of her personal information with the CRA. She may also want to sign up for theDirect Depositoption.
To get started please go to this link:CRA sign-in services. It only takes a few minutes to prepare, and make sure to note all your answers and credentials.
For further assistance if needed, pleasecontactus.