Hi! I am setting up my own practice and want to make sure that I don’t miss anything. Besides these documents, what else does the client need to sign for a tax preparation engagement?
Thank you!
The T1013 is no longer in use.
“AUT-01 Authorize a Representative for Access by Phone and Mail” is the current form.
@SmallBizGuy Thank you for the clarification!
The ‘new’ CRA process of not requiring clients sign the T1013 is definitely easier in terms of signatures and paperwork! Unless, the client doesn’t have access to their MyBusiness account 
T1013 was for authorizing access to PERSONAL tax accounts, which has been replaced by AUT-01. If filed through tax software, it still gives you (instant) online access (through RAC).
RC-59 was the equivalent for BUSINESS accounts, which has been replaced by AuthRepBus (in tax software). That, or the form you generate on RAC and get clients to sign, now gives you only OFFLINE access unless the client logs into their MyBusiness account and approves the request.
You don’t need either of these to FILE a tax return - the T183 itself is the form that authorizes you to FILE a T1 or a T2, etc. (once signed by the client).
There are other forms that need to be signed by T1 clients, when they are applicable. For example:
T1032 - pension splitting
T1135 - foreign income verification
T2091 - designation of a personal residence
T1A - request for loss carry-back