Your W-2 has nothing to do with mortgage interest. The W-2 is entered under the Personal Income tab where it specifically asks for W-2 income.
Mortgage interest reported to you on a 1098 is entered under the Deductions & Credits tab in the "Your Home" section.
THis is assuming you own the home and do not rent it out or use it for anything other than your primary residence, 2nd home, vacation home or other personal pleasure use.
If it's for rental property that you own and rented out in 2019, then you'll be asked for mortgage interest in the Rental & Royalty Income (SCH E) section of the program as you work it through and get to the point where it will ask you for that interest amount in the rental expenses section.