Hi @sulekhalive,
To delete a poll for a scheduled meeting, you can use this endpoint:
https://marketplace.zoom.us/docs/api-reference/zoom-api/meetings/meetingpolldelete
To update whether polling is enabled for an entire account, you can use this endpoint:
https://marketplace.zoom.us/docs/api-reference/zoom-api/accounts/accountsettingsupdate
Meeting Chat cannot be controlled via API, you will need to use the UI/Client for this:
https://support.zoom.us/hc/en-us/articles/115004809306-Controlling-and-disabling-in-meeting-chat
For Q&A during a Webinar, you will need to set this in the UI:
https://support.zoom.us/hc/en-us/articles/203686015-Using-Q-A-as-the-webinar-host#h_cc67500f-3ceb-400d-8f3e-4ffdfccccf3f
Alternatively, you might consider using a template for webinars, which can be applied via API. This is covered in this thread:
Let me know if this helps to clarify,
Will