It depends on which program you are using. Are you using the online version or are you using a desktop version?
In the desktop version, you can select the "Forms" view and you can see them filled out. In the online version you can go to "Tax Tools" then "Tools" and then "View Tax Summary" then to the left you will see "Preview my 1040". The 1040 is the only form you can preview in the online version.
