Documents by the Royal Thai Embassy or Consulate in the document's country of origin. The legalization confirms that the document is genuine and legally recognized by Thai https://www.evernote.com/shard/s485/sh/7723a992-6e5d-0a61-0c6a-78cb2e0cc669/5RNjsKGu1mbovUjvIRacVmokCzuUXuBEiarXPre-lMEsmOG0M3n4XwDg2g