Sorry I don't think I clarified enough. To fill out your expected taxes you have to do calculations to determine the proper deductions. So very often you do end

Sorry I don't think I clarified enough. To fill out your expected taxes you have to do calculations to determine the proper deductions. So very often you do end up owing because your original paperwork wasn't quite right. The software is not necessarily "required" you could fill out all of these forms by hand and the IRS also provides online software to aide in filling some of the forms. Many people do do this if they have very simple tax situations and they don't mind dedicating some time to it. However, due to the complexity of the filing it often is just easier to pay turbotax, HR block, etc to ask some questions and auto-populate the forms for you. There is also weirdly specific forms you sometimes need for certain deductions/situations (foreign income, foreign bank accounts, investments, crypto, living on a college campus, school supply tax reductions, etc) and its not always obvious when you need to fill these forms out, you could read the IRS website but that's excruciating. So often times these tax softwares also ask questions to help you determine what forms are necessary to have a complete return or help you maximize your deductions by finding the ones you qualify for.