To create a custom account field, the following permissions are required.
Account permission: the user should have permission to manage account.
{
    "accountCustomFieldMeta": [
        {
            "id": "1",
            "fieldLabel": "Text Example",
            "fieldType": "text",
            "fieldOptions": null,
            "fieldDefault": 1,
            "fieldDefaultCurrency": null,
            "isFormVisible": 0,
            "displayOrder": 1,
            "personalization": "",
            "knownFieldId": null,
            "hideFieldFlag": 0,
            "createdTimestamp": "2019-04-23 15:34:00",
            "updatedTimestamp": "2019-05-03 15:16:51",
            "links": {
                "accountCustomFieldData": "https://:account.api-us1.com/api/:version/accountCustomFieldMeta/1/accountCustomFieldData"
            }
        },
        {
            "id": "2",
            "fieldLabel": "Multiple Choice Example",
            "fieldType": "multiselect",
            "fieldOptions": [
            	"Option 1",
            	"Option 2",
            	"Option 3"
            ],
            "fieldDefault": 1,
            "fieldDefaultCurrency": null,
            "isFormVisible": 0,
            "displayOrder": 2,
            "personalization": "",
            "knownFieldId": null,
            "hideFieldFlag": 0,
            "createdTimestamp": "2019-04-23 15:34:00",
            "updatedTimestamp": "2019-05-03 15:16:51",
            "links": {
                "accountCustomFieldData": "https://:account.api-us1.com/api/:version/accountCustomFieldMeta/1/accountCustomFieldData"
            }
        }
    ]
}
200200
