How Master seed is generated using Bitcore API? Can someone please explain how to get Master Seed when a new HD keys is created using Bitcore APIs?

My purpose is to implement wallet service in my application using Bitcore APIs.

Refer this link here
In case you are talking about mnemonic seed use this - 

Install bitcore-mnemonic

npm install bitcore-mnemonic
bower install bitcore-mnemonic


Then use it to generate mnemonic seed - 

var Mnemonic = require('bitcore-mnemonic');
var code = new Mnemonic(Mnemonic.Words.ENGLISH);
code.toString(); 
// army van defense carry jealous true garbage claim echo media make crunch...

var xpriv = code.toHDPrivateKey();


If you just want to generate a private from bitcore api you can use this function - 

var bitcore = require('bitcore');
var HDPrivateKey = bitcore.HDPrivateKey;


Please note there is no rule to generate a private key. A private key is just a random string. It could even be your name or a whole article. But you must create a private key that is 'random' in nature. Also never use programming language functions like md5 hash or something to generate a private key because they are not truly random. 

Bitcore api, however, provides an easy way to generate a private key using the above method. From there you can proceed as usual.

var bitcore = require('bitcore');
var HDPrivateKey = bitcore.HDPrivateKey;

var hdPrivateKey = new HDPrivateKey();
var retrieved = new HDPrivateKey('xpriv...');
var derived = hdPrivateKey.derive("m/0'");
var derivedByNumber = hdPrivateKey.derive(1).derive(2, true);
var derivedByArgument = hdPrivateKey.derive("m/1/2'");
assert(derivedByNumber.xprivkey === derivedByArgument.xprivkey);

var address = derived.privateKey.toAddress();

// obtain HDPublicKey
var hdPublicKey = hdPrivateKey.hdPublicKey;