If you are preparing your return separately from your partner, then there will be no calculation of your partner’s income. It will be done on their own return.

Here is what you can do if you don’t know your spouse’s income: https://turbotax.community.intuit.ca/replies/2647950

If you want to prepare your return together with your partner, and it is asking you for their Net Income, then you have accidently started a single return. You’ll need to start over if you want to do both returns at the same time.  To do this select Start A New Return under My Account & Returns in the left side menu. When you are asked the question “Who are you preparing this return for?”, select My spouse/partner and me.

Later, you can select View All Tax Returns under My Account & Returns and click on the trash can next to the return you no longer want to delete it.