This article explains how to enable page numbering through REST API.
Instructions
Follow the below steps.
Create a Confluence page without enabling the Numbered Heading macro.
Copy the page ID as per the screenshot.
Go to the Postman or any REST API app (based on your environment).
Add this REST endpoint link to the POST section of the tool.
https://example.atlassian.net/wiki/api/v2/pages/XXXXXXXX/properties
Change the page ID based on the specific Confluence page.
Add this code in the Body section.
{"key": "nl_avisi_nh", "value": { "isEnabled": true } }
Click Send.
Refresh the Confluence page and verify that the Numbered Heading is enabled.
Refer to this link for Atlassian latest Confluence Cloud REST API https://developer.atlassian.com/cloud/confluence/rest/v2/api-group-content-properties/#api-group-content-properties