Hi Harpreet,
There are various levels of customization that you can perform here. You can use segmentation-based dynamic content: https://community.marketo.com/MarketoTutorial?id=kA250000000Kz0SCAS You can use email scripting to pull content from custom objects, and do large amounts of conditional display: http://developers.marketo.com/documentation/email-scripting/ You can also do completely per-lead emails with fully customized content via requestCampaign API calls: http://developers.marketo.com/documentation/rest/request-campaign/ Blog guide here: http://developers.marketo.com/blog/sending-an-email-with-dynamic-content-from-marketo-using-the-api/