Hello Ttaenang, Happy Wednesday!!
I would like to recommend another way of doing it through SUKHIBA - Its an all-in-one commerce platform which enables customers build customer relationships, set up your own catalogue or sync your existing Shopify site. So you as the store owner you are able to give credit of a n agreeable amount. Attaching a screen recording URL https://drive.google.com/file/d/1T0tHpyFKcFXwa9pypTZ1F8Ab97fzey9a/view?usp=sharing Happy to book a demo with you to expound on this.