Transferwise is one of the best 1s for sure. But it’s impossible to pick an absolute winner without knowing the details. Like where you need 2 wire the funds and how you are going to pay. Is is a transfer to TH or from TH etc
Formally you only need a passport valid at the moment you apply (every visa is transferable) but some immigrations may not like if you passport expires soon
But 6 months and more is always considered as 👌 wherever u go