There is no fixed format, upload them as you see fit, I i submitted copies of original contracts. cut n pasted client emails of appreciation. with redaction of client private info.
DTV is not just for youngsters or soft power applicants. Many use it to work online, run businesses while in Thailand. Significant numbers are in their 40s - 60s.
Swaine, DTV needs 500K THB or equivalent currency in a personal account. Need to show you work online for a non Thai firm via contracts, CV, portfolio etc. You should check the main DTV group on Facebook, lots of tips on how to apply. You can get USD income while in Thailand with the DTV which is great way to save some of your retirement funds