Once you have completed entering your data and the return passes all of our validation rules, you will have the option to Sign the return.  Verify that the Sign Return menu on the home ribbon is available to be selected.  If it is, then there are no issues with the return.  If it is not available, click the Show Errors option on the home menu and it should show you what the issues are with the return. Once those issues are corrected, the Sign Return option will become available.