You need to upgrade to Deluxe to itemize deductions. Mortgage Interest is an Itemized Deduction.
Even in Deluxe, you won't see a change in your refund until all your itemized deductions in total exceed your standard deduction.
So, you would need to upgrade and continue entering your deductions, and then you'll see a change in the refund amount, as soon as all your deductions total more than the amounts below.
Single $6.300,
Married Filing Joint or Qualifying Widow $12,500,
Head of Household $9600
