To grab MAC address first we have to enable device WIFI, after enabling it we can get the MAC address.

public static String macAddress(final Context context){
        WifiManager wifiManager = (WifiManager) context.getSystemService(Context.WIFI_SERVICE);

        String address;
        if(wifiManager.isWifiEnabled()) {
            // WIFI ALREADY ENABLED. GRAB THE MAC ADDRESS HERE
            WifiInfo info = wifiManager.getConnectionInfo();
            address = info.getMacAddress();
        } else {
            // ENABLE THE WIFI FIRST
            wifiManager.setWifiEnabled(true);

            // WIFI IS NOW ENABLED. GRAB THE MAC ADDRESS HERE
            WifiInfo info = wifiManager.getConnectionInfo();
            address = info.getMacAddress();
        }
        return address;
    }

To know your device IMEI number, first generating device id from TelephonyManager class

public static String getIMEI(final Context context) {

        TelephonyManager tm = (TelephonyManager)context.getSystemService(Context.TELEPHONY_SERVICE);
        String imei_number = tm.getDeviceId();
        return imei_number;
    }

//add permission in your manifest file
	<uses-permission android:name="android.permission.READ_PHONE_STATE"/>

Android Unique ID

public static String getuniqueId(final Context context) {
	String androidId;
	androidId = System.getString(this.getContentResolver(),Settings.Secure.ANDROID_ID);
	return androidId;
    }