I'm planning to apply for the evisa in Vietnam through Thai soft power (Muay Thai).
I'm currently in Thailand. Do I have to leave thailand first before I can submit my online application on [members only]/
TLDR : Answer Summary
To apply for the eVisa while currently in Thailand, you must first leave Thailand and go to Vietnam. The application requires you to provide your current location and the embassy will need your address in Vietnam. Attempting to apply for the eVisa from within Thailand may lead to rejection and potential loss of the visa fee.