You didn’t say where you are from. I’m from England and I came through immigration last month with the same visa as you, I showed my visa on my mobile phone and the guy just added a little note in my passport confirming the 90 days. It’s important to show your visa or you might just end up with a tourist visa stamped into your passport, with only 60 days.
You will need to apply from out of Thailand. Make sure you have the relevant documentation. An issue always arises when trying to upload bank statements. Two possible reasons for this is the size of the statements, you will need to compress them (they all have to be part of one pdf document) if they are over the required size. A second common reason for failure is the hardware that you are using. Don’t try and complete the application with an iPhone or iPad, use a laptop or desktop. Good luck 👍
I came through last week from the uk, same visa as you. I just put car, and some random date inside my visa period. Got through easily, no questions asked
The problem with this site is that there are so many different answers by different people, which contradict each other. It’s a complete minefield of advice. Somewhere in there is the answer…but who knows where ?