Many students self-report ACT and SAT scores on the Common App (under Testing — It is optional). But until very recently, most colleges and universities still required (or strongly suggested) that the applicant follow up by sending the official score reports in addition. This, I imagine, would prevent the applicants from inflating or fabricating scores.
However, in the apparent interest of saving families the expense and the frustration of going through ACT and the College Board for the SATs, some schools now allow the students simply to self-report scores on the Common App. They only require verification if the student decides to attend that school.
In addition, this change in policy would have the effect of encouraging more students to apply to schools that don’t require the extra steps and expense, so that’s good for their business as well.
If you double click on the name of the school on the drop-down list, the school policy shows up. Some schools clearly indicate that self-reporting is quite sufficient; others accept self-reporting or direct reports to the schools from the ACT or College Board; and certain schools will have clarifications (out of state/international students, etc.)
Read the criteria from each school very carefully. It is not always as clear-cut as it would seem!