If you are creating pages with the Confluence API and you want to turn on numbering, you can use the numbering API.
The request payload that you should send for this request is as documented in Page properties.
Curl example
curl 'https://localhost:1990/confluence/rest/numberedheadings/1.0/page-configuration/360482' -X 'PUT' -H 'Content-Type: application/json' --data-binary '{"isEnabled":true,"numberFormatField":"decimal","startingNumberField":"3","startingHeadingField":"H1","skipHeadingField":"","customFormatFieldH1":"","customFormatFieldH2":"","customFormatFieldH3":"","customFormatFieldH4":"","customFormatFieldH5":"","customFormatFieldH6":""}'
The request payload that you should send for this request is as documented in Page properties.
Curl example
curl 'http://localhost:1990/confluence/rest/numberedheadings/1.0/space-configuration/ds' \ -X 'PUT' \ -H 'Content-Type: application/json' \ --data-binary '{"isEnabled":true,"numberFormatField":"decimal","startingNumberField":"2","startingHeadingField":"H2","skipHeadingField":"","customFormatFieldH1":"","customFormatFieldH2":"","customFormatFieldH3":"","customFormatFieldH4":"","customFormatFieldH5":"","customFormatFieldH6":""}'