Zoho Mail Add to CRM - need to create a lead not a contact

Zoho Mail Add to CRM - need to create a lead not a contact

I have the Zoho Mail Add On.
When I select an email and choose add to CRM,
it creates a contact.
Why can't I create a lead.
I have lots of incoming email from people that are new leads?
Can I have add to CRM create a lead instead of a contact?
If not, can I convert a contact to a lead?