>>64391502
And since you want official documentation
https://irp.fas.org/doddir/army/ar670-1.pdf
>The full-color U.S. flag cloth replica is worn so that the star field faces forward, or to the flag’s own right. When
worn in this manner, the flag is facing to the observer’s right, and gives the effect of the flag flying in the breeze as the
wearer moves forward. The appropriate replica for the right shoulder sleeve is identified as the reverse side flag.