Also any search will answer it immediately:
*"If a served ball bounces twice in the receiver’s service box, it is considered a valid serve, an "ace", and the serving team immediately wins the point. The returner must hit the ball before the second bounce."*
However, people who have been given contradicting advice in person need more confirmation than Google results or an old Reddit theread. They want discussion and live replies. This is why there will always be discussion threads over repeating topics, forever, in all forums or social media.