Thai is a trade name on a kratom label, like maeng da and bali. Products here include Super Speciosa‘s White Thai powder, which is pure Mitragyna speciosa leaf.
The name does not say. The Super Speciosa White Thai pouch reads Product of Indonesia.
All three are trade names for the same plant, Mitragyna speciosa. Color comes from drying and handling, not from the name.
Yes. It is plain leaf powder. Start with the suggested serving printed on the package.