Can anyone explain why order apis are used(place, modify, cancle) al this apis?
Could you please provide more details about what you want to know? Your question is not clear.
can we connect or get your number i need guide in apis
To get started, you need to create your app using the following guide: How to Create an API App.
I recommend familiarizing yourself with the API documentation available here: Upstox API Documentation.
Additionally, you can refer to the sample code provided to help you get started quickly: Upstox Example Code.