If you are filing a tax return in Canada for the first time then you will not be able to create a CRA My Account login. You will have to file your return, and then wait until you get your Notice of Assessment (NOA), before you can create a login. You don't need a CRA My Account login to be able to file online using NETFILE, but most people filing for the first time can't use NETFILE. So, you will need to print and mail your return.