You can apply to be your husband's legal representative for tax purposes, but it is not required that you do this to use TurboTax.
This CRA page tells you how to register for Represent a Client:
natemc3287
New Member
AS2024
Returning Member
sadiefinch1
New Member
2022rob-lindatax
New Member
0962-51251
New Member
You have clicked a link to a site outside of the TurboTax Community. By clicking "Continue", you will leave the Community and be taken to that site instead.