How do I know I filed? I paid for two returns. I did a joint return. I was only able to file the joint return. Is that the way it is supposed to work??

I assume  the joint return is all that is required. 

Filing

When you prepare your taxes together with your spouse as a joint return, each return is NetFiled individually and receives its own unique NetFile Confirmation Number. As long as you have received a confirmation number for each of you, you can rest assured both returns have been successfully filed.

https://turbotax.community.intuit.ca/replies/2864697