How to read POST response and display on page?

I would like to retrieve the

minDateTime

value from my installed app and then display it on my page. Please see the attachment for clarification. Any help appreciated. Thank-you!

https://docs.zapiet.com/reference/store-pickup/pickup-calendar

This is more of a frontend javascript topic than anything to do with OS2.0 themes.

https://www.google.com/search?q=javascript+How+To+Read+POST+Response+And+Display+On+Page

example > https://stackoverflow.com/questions/71491954/how-to-show-the-response-on-page

etc