How to generate objectid for each element of nested array of the document?

    "name": "int-q18-24",
    "status": "active",
    "domain": [
        {
            "name": "base-infra",
            "status": "active",
            "services": [
            ]
        },
		{
            "name": "catlog",
            "status": "active",
            "services": [
            ]
        }
    ]
} >

This is document which consisted array field. I want to generate objectid for each array elements. need help