Usually they charge for the customization!
These yeti cups above are some I have ordered from the in the past and the engraving is really nice laser engraving!
My only suggestion is to carefully pick the color cup you do it on. I did a blue one time and it didn’t look great with the silver that shows after the laser.
I think white is the best color to do, but that’s just my opinion!
Engraving is free for just 1 more day!
https://thefreebieguy.com/yeti-custom-tumblers-would-make-the-perfect-fathers-day-gift/