How to get Client credentials from Shopify Public App?

Shopify Apps
1

Hello,
how to get Client credentials from Shopify Public App?

not from the Partner Account, I want to get using it programmatically.

I’m developing an App using Shopify PHP App Template (PHP+ReactJS App).

now in some cases, I need Client credentials (Client ID) programmatically, I have R&D for that, but nothing found,

can someone please help me with this?

need client credentials using Controller, Router, and Reactjs Component.

Thanks.