Hi @poojamehta_ids,
If you mean that you’d like modify the Alerts themselves so they contain additional information and then have that reflected in the Get Alerts REST API response then you can add the additional information/fields you want stored to the Alert data class and then update the toXContent and parse so that data can be indexed and subsequently read back.
You might also want to update the alert mapping so it recognizes the field the way you want it to.
The Get Alerts API is essentially returning a search response format of the fetched Alerts so these changes should be sufficient to have those additions reflected in there.
If you have a specific example, I might be able to provide further assistance if the approach above isn’t what you’re looking for.