Hi Nitesh, 

To create a user account using one of your domains, use the following POST request, and include the authorization described in Authorize requests. For the request query string properties, see the API Reference
 

POST https://www.googleapis.com/admin/directory/v1/users

The following JSON shows a sample request to create a user
 

{
"primaryEmail": "liz@example.com",
"name": {
 "givenName": "Elizabeth",
 "familyName": "Smith"
},
"suspended": false,
"password": "new user password",
"hashFunction": "SHA-1",
"changePasswordAtNextLogin": false,
"ipWhitelisted": false,
"ims": [
 {
  "type": "work",
  "protocol": "gtalk",
  "im": "liz_im@talk.example.com",
  "primary": true
 }
],
"emails": [
 {
  "address": "liz@example.com",
  "type": "home",
  "customType": "",
  "primary": true
 }
],
"addresses": [
 {
  "type": "work",
  "customType": "",
  "streetAddress": "1600 Amphitheatre Parkway",
  "locality": "Mountain View",
  "region": "CA",
  "postalCode": "94043"
 }
],
"externalIds": [
 {
  "value": "12345",
  "type": "custom",
  "customType": "employee"
 }
],
"relations": [
 {
  "value": "Mom",
  "type": "mother",
  "customType": ""
 },
 {
  "value": "manager",
  "type": "referred_by",
  "customType": ""
 }
],
"organizations": [
 {
  "name": "Google Inc.",
  "title": "SWE",
  "primary": true,
  "type": "work",
  "description": "Software engineer"
 }
],
"phones": [
 {
  "value": "+1 nnn nnn nnnn",
  "type": "work"
 }
],
"orgUnitPath": "/corp/engineering",
"includeInGlobalAddressList": true
}

See this documentation to learn more
You have to build your code similar to what is shown in this video

Anudeep