I use a roller jack under the shackle of the axle, then jackstands and/or wood blocks as needed to secure the trailer while in the air. I did two at a time, off one axle. My local garage suggested I only bring in two at a time, leaving one pair of tires on one axle as an additional safety.
I have also used bottle jacks - actually, the tire change jack on my F250 works quite nicely to jack up my TT if needed. You can use a small work block to protect the axle / shackles depending on how your axles are setup.
If you have a tire shop do it, better make sure they know how to safely jack up a travel trailer. So many vehicles today just require that the jack be put under the outside edge of the vehicle to jack them up, a tire change place may do that out of habit to your TT.