Please see below for how to change your filing status to "Married Filing Jointly".
To change your filing status in TurboTax Online:
1. Go to "Personal Info" at the top of the page
2. Select "Edit" next to marital status
3. Select you are "Married", then answer the
question "Do you want to file this return together with your spouse?"
4. Answering "No" will get you the Married Filing
Separately status
5. Continue answering the questions in this section until finished
https://ttlc.intuit.com/replies/3302320