Same question, you want to create a new field?
Do a search for "create new field in marketo" and you'll find what you need.
Admin>Field Management>New
if this is a Marketo only field, that's ok. If you need Salesforce to see it, you should create it in SFDC first.
Lakshmana, not sure what you're referring to?
What is the requirement? Are you trying to create new fields in Marketo or just add fields to a form?