A tax treaty is a bilateral (two-party) agreement made by two countries (the US and another foreign country) to resolve issues involving double taxation. The tax treaty can lower your taxable income, depending on the exact amount the tax treaty is that you are eligible for. You can check the main conditions which might make you eligible for the tax treaties applying to your home country here: https://www.irs.gov/businesses/international-businesses/united-states-income-tax-treaties-a-to-z
Please note that if you do NOT see the sub-step related to the tax treaty (Step 3 - Let's talk money - Tax treaty verification), then you might not be eligible for the tax treaty. Keep in mind that whether or not your country has a tax treaty does not mean you fall under ALL conditions to claim the benefit. If you have entered your details correctly, Sprintax will automatically determinate your eligibility and ask if you wish to use the tax treaty exemption on the Tax treaty verification sub-step if applicable.