As you can imagine the Thai tea and coffees are served over ice as a cold drink rather than a hot drink. Although Starbucks are everywhere, and Costa Coffee shops are practically on every corner, we still have our own, older brands of tea and coffee.
See also 'Iced Sweet Thai Tea' on my Life blog for a video of how this is sold.
In the photograph above on the left, this is ready made tea from โอเลี้ยง (O-leang brand), and on the right I've made O-leang brand coffee with evaporated milk the way it's drunk in Thailand. Both served over ice.
The bottles of the product are shown below, both are ready made, simply pour over ice and serve with evaporated milk (e.g. carnation, not the sweetened condensed milks) if you want milk coffee and milk tea.