How to get Task Custom Fields Ids

How to get Task Custom Fields Ids

Hi All,
I hope you all are doing well!!!
I am creating projects and Tasks in ZOHO from an external platform.

I have created a custom field in the task. And now I want to set that Field value while creating new task using API .
So I want id of the custom field. Where I can get Task custom field id. Which API should I use to get id of Task custom field? and again can I see the custom field id on Zoho project UI.??