How do Americans apply for the Thailand DTV visa from the Philippines, Vietnam, or Cambodia?

You can not be in Thailans when applying DTV. you MUST exit Thailand and submit application online

you appear to have a sketchy grasp of how you get visas to thailand 🙁

ALL thai consulates in the world are online at the eVisa web-portal.

You go to a country whose thai consulate you're going to apply thru, you log into the eVisa website, you apply online, upload the correct documents, proof you're in that country, pay online and then you wait in that country until the visa is approved or rejected.

Once it's approved they email you a PDF you print out and present with your passport when you stamp into thailand. 🙂

Every person use the same website:

And you use the current location and you choose the Embassy or Consulate in your region.

You don't "send" your application anywhere. You submit it online through the e-visa system, and choose the embassy that will process it based on where you physically are located at the time you submit it.

You send it to the embassy in your location. I was in Vietnam, so sent there