A relatively senseless question but... do you actually know how to fold your dress shirts?
In case you need help, here's 3 methods you may consider. These 3 methods would be useful specially if you're packing up for a trip.
A point to note that no one method is a sure way to completely prevent dress shirts from wrinkling.
Your dress shirts are bound to have some form of wrinkling; however, several factors will determine the amount of wrinkling: they are the fabric type and weave of the shirt, the duration and how tightly your garments are packed.
It is hence advised that you should always schedule time to touch up your dress shirts before wearing, especially for an important occasion.