@Vinod_Rath I would recommend using the REST API to work with custom fields for Contacts.
Use GET /contactCustomFields to view the custom fields that you have configured.
Use PATCH /contacts/{contactId} to update a Contact with values for the custom fields you want.
The body of the PATCH /contacts/{contactId} request might be something like:
"custom_fields": [
{
"id": 2,
"content": "B0018ZW7CA"
},
{
"id": 0,
"content": "2017-04-28T14:33:00-0700"
}
]