They'll deliver said envelopes to your stateroom on the night before the cruise ends. They also give you a sheet to fill out which makes it easy to charge the tips to your stateroom account. You can always use cash, too.
I printed my own "Mousekeeping" envelopes and also the tip envelopes for our servers & I also included a small card (like a business card) with Mickey on it and our name and address and a line that said something along the line of "With our sincere appreciation" and then delivered them myself. I wanted to add a little personal touch.
GET UP TO A $1000 SHIPBOARD CREDIT AND AN EXCLUSIVE GIFT!
If you make your Disney Cruise Line reservation with Dreams Unlimited Travel you’ll receive these incredible shipboard credits to spend on your cruise!