Schedule B reports the interest and dividend income you receive during the tax year. This form cannot be filed using TurboTax Free Edition. However, in 2020, a Schedule B is only necessary when you receive more than $1,500 of taxable interest or dividends.
You are welcome to start your return in the Free Edition, but If we detect that your tax situation requires expanded coverage, like deductions for owning a home or self-employment income, we'll prompt you to upgrade to a version that supports the forms you need. Refer to the following Help Article for more information: Why do I have to upgrade from Free Edition?
Additional reference: What Is a Schedule B IRS Form?