Want to create web api for post data header and details table

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C#7.0

I want to create WEB API for below format just like Purchase Order Format

[
    {
        "PO_NUMBER": "12345TSTPO",
        "PO_DATE": "12/27/2018 12:00:00 AM",
        "PO_EXPIRY_DATE":"12/27/2018 12:00:00 AM",
        "ORG_MOD": "ALI",
        "PO_VALUE": "214",
        "VENDOR_CODE": "Vendor WarehouseAddress",
        "PO_ISSUE_LOC_CODE": "1009307294",
        "PO_DELV_LOC_CODE": "IN019387820-S",
        "VENDOR_DETAIL": "S-VIJAY SALES",
        "PO_ISSUE_LOC_DETAIL": "Vendor Address ",
        "PO_DELV_LOC_DETAIL": "999",
        "PAYMENT_TERMS": "2147483647",       
        "PoDetail": [
            {
                "PO_NUMBER": "test",
                "PO_LINE_NO": "1",
                "EAN": null,
                "ITEM": "",
                "ARTICLE_NO": "Clothes Washer_Turbo Drum",
                "QTY": 25,
                "UOM": "EA",
                "BASE_COST": "12211.56000000",
                "SALE_TAX": 0,
                "TOTAL_BASE_VALUE": 54952.02,
                "TOTAL_TAX_VALUE": 360241.02,
                "DELIVERY_INSTRUCTION": "63936951",
                "PO_LINE_EXPIRY_DATE]": "12/27/2018 12:00:00 AM"
            },
            {
               
                "PO_NUMBER": "test",
                "PO_LINE_NO": "1",
                "EAN": null,
                "ITEM": "",
                "ARTICLE_NO": "Clothes Washer_Turbo Drum",
                "QTY": 25,
                "UOM": "EA",
                "BASE_COST": "12211.56000000",
                "SALE_TAX": 0,
                "TOTAL_BASE_VALUE": 54952.02,
                "TOTAL_TAX_VALUE": 360241.02,
                "DELIVERY_INSTRUCTION": "63936951",
                "PO_LINE_EXPIRY_DATE]": "12/27/2018 12:00:00 AM"
            },
            {
               
                "PO_NUMBER": "test",
                "PO_LINE_NO": "1",
                "EAN": null,
                "ITEM": "",
                "ARTICLE_NO": "Clothes Washer_Turbo Drum",
                "QTY": 25,
                "UOM": "EA",
                "BASE_COST": "12211.56000000",
                "SALE_TAX": 0,
                "TOTAL_BASE_VALUE": 54952.02,
                "TOTAL_TAX_VALUE": 360241.02,
                "DELIVERY_INSTRUCTION": "63936951",
                "PO_LINE_EXPIRY_DATE]": "12/27/2018 12:00:00 AM"
            }
        ] }
]

What I have tried:

i try to Post data in JSON and get on API Controller in JObject but not working