Should I fill in two separate mortgage companies for the same mortgage?My mortgage was transferred to another company, so I now have 2 different 1098 forms.

Yes. You must enter both of your 1098's separately. 

To enter your 1098's, you can follow these steps in TurboTax:

1. Open your return.
2. Search for 1098 with the magnifying glass tool at the top of the page.
3. Click the Jump to 1098 link at the top of the search results.
4. Answer yes to Did you pay any home loans in 2020?
5. Continue on the page that says Get ready to be impressed.
6. Rather than entering a bank name or sign-in URL, scroll down and click on Change how I enter my form.
7. Click on Type it in myself on the bottom right.
8. Follow the on-screen instructions. 
9. Once the first 1098 is inputted, you will get to the Mortgage deduction summary screen.
10. Click on Add another 1098.