No they didn’t. The CDC and Dr. Anthony Fauci, who the president hand-selected to be on the coronavirus task force, have stated otherwise. Repeatedly.
If you’re referring to a CDC-published study (that I’m sure you didn’t actually read) referenced by another wishful thinker, it was inconclusive but It said it was worthy of further study. Some subsets of the study found that when everyone who participated wore masks and practiced hand hygiene, the virus transmission rate dropped by over 50%.
That same study also specifically didn’t include N95 masks or their equivalents, which have a much higher filtration rate than tying a sock around your face.