Hello guys

I'm new Odoo user with good background in Python and some front-end stuff, I'm using Odoo 18 and trying to create an app then link it with Accounting Module, so my question is: Should I create the app inside Accounting Module? Inventory? for better connection with database without using codes? or do I need some coding? what if I made the app outside can I integrate it with Accounting Module even with limited abilities?

I need your best procedure ... 

Thank you