How can I submit a cover letter and additional documents for my remote work permission in Thailand?

The user is inquiring about the submission process for a cover letter and the necessary documents for obtaining permission to work remotely in Thailand. They noted that there is no specific section in the application for these items. Commenters advised merging all related documents, such as the cover letter, portfolio, and company registration, into a single PDF for submission. They also highlighted the need for a permission to work document and suggested submitting it alongside the contract.