For the 90-day non-O visa from the Thai embassy in Canada, you don't need to show any money in a Thai bank account.
But if you want to apply for the 1-year extension in Thailand, you don't have a choice. The Canadian embassy in Thailand stopped income verification on April 1st of this year. So your only option is proof of 400,000 baht in a Thai bank account in your name only.
For Thailand, always print everything. The email you received with your visa should have instructed you to print it.
Hand it over with your passport and final boarding pass when you get to passport control, then when you step away, check the stamp you received to make sure it's correct. Do this every time you step away from passport control.
And don't forget your TDAC when you're 2-3 days away from traveling.
It's an extension. It extends your time. It's added on to the end because the extension you'll be applying for will be for the reason as the entry stamp you receive.
the only time it needs to show as international transfer is when you're trying to convert from tourist to non-O visa based on retirement inside of Thailand. The one year extension doesn't have that requirement.
You cannot get a DTV inside of Thailand. It's only available from Thai embassies through the e-visa system.
It's also not as simple as just applying. You need to qualify first, and then provide all the paperwork as part of your application showing that you qualify.