See: https://www.makroclick.com/en
You can register with either an email address or your telephone number. If you have a Makro card, register with the card number, although you can also register without a Makro card.
I did not see anything about a minimum order amount, so if there is a minimum I don't know what it is. If anyone finds out, please post.
If you have any questions, Makro's call center number is: 02 335 5300
I prefer to do all my shopping personally, but not everyone has a car. If I was using a motorbike and was going to order more than I could reasonably carry on the motorbike, I would go to Makro, shop and make a list of everything I want to buy, maybe buy a few items, and then use the app to order and have everything else delivered.

photo from Pattaya Mail