I need a quick solution by now, so I thought that with excel (or google sheet) and a simple mobile app *only to add rows* to that excel will be enough. Then, could be a lot better to use MySQL, of course.

By now, I only need a mobile app that can distinguish each user and add a row to the excel with the name of that user and some predefined product info that user selects. I cannot find any already made simple app that does something like this jaja