If you want your colleges to consider your ACT scores as well as your SAT scores, then you need to order an official ACT score report. If your ACT’s are better than your SAT’s, that’s the wise move.
You can use a “concordance chart” like this one to compare tests: https://www.act.org/solutions/college-career-readiness/compare-act-sat/
You can then decide if you want to report all scores.
Since you already sent your SAT scores, there is no need to send the official ACT scores (or even to report the ACT scores on your applications) unless you did better on the ACT.
It’s confusing, isn’t it?