The software has been updated for this already. It shows you are using a desktop software product, so make sure you have updated your program. Go to TurboTax (next to your Apple Icon) and click Check for Updates.
You can then return to the Mortage Interest section and add your insurance premiums (see screenshot)
Also, see the following article for some of the limitations around mortgage insurance as not everyone is able to deduct this amount or will see a tax benefit
https://ttlc.intuit.com/replies/3301952
