can be done anywhere that has an Thai embassy or consulate but you are required to be in that country from time of application to approval. I'm USA citizen, and applied in Taipei.
I submitted Schedule C and local city business tax form. Screenshot from website, CV, and remittances records. No corporate identity as Sole Proprietorship.
I submitted Monday morning and had to go back to check in the afternoon. Was told I can pickup passport Tuesday 4 pm. It was stressful as the person who previewed my application didn't seem to understand what he was looking at.Best reason to come to Taipei would be in person they don't accept payment until it's been reviewed and approved. Not sure why the 24 hr delay to retrieve the passport and sticker.