How to submit supporting documents with my return? Can I submit to CRA separately, but still file the main return through TurboTax?

[evan4]

There are other questions like this.  I understand that I can submit supporting documents directly in CRA My account.  I just want to confirm though that if I do that, I can still file the main return through TurboTax, right?  And then just go into CRA My Account and upload my other thing there, right?  (The form is T1142 but I'm asking generally also)

Here's the CRA information on submitting documents online: https://bit.ly/2TNXmCn

Edit:  CRA won't let me submit T1142 online.  They have a specific list of documents that can be submitted that way.  The rest have to be mailed in.  Still wondering if it's okay to file online with TurboTax, and then mail in the T1142.

[TurboTaxSusan]

The NETFILE system is run by the CRA, so while TurboTax won't have a problem creating your return, the CRA may reject your return if there is info they need. 

You should double check with them if it will cause a problem. If you are in Canada or the United States, you can call the CRA at 1-800-959-8281. If you are somewhere else you can call 613-940-8495. Here are more ways to contact the CRA: https://www.canada.ca/en/revenue-agency/corporate/contact-information/telephone-numbers.html