Here is a list of all the ways leads can get into Marketo.
Marketo Forms On Marketo Landing Pages
When leads fill out forms on your landing pages, they are automatically added to your Marketo lead database.
Marketo Forms On Non-Marketo Landing Pages
You can "copy" the form HTML from Marketo, make slight changes and add it to your own website. Leads filling out these forms are also added to the Marketo lead database. Note, progressive profiling and form pre-fill are not available in this situation.
Marketo Forms On Non-Marketo Landing Pages Using Iframes
This method allows you to use a Marketo form on your own website without losing form pre-fill and progressive profiling.
Import a list of leads into the Marketo lead database.
The CRM Sync will pull down and keep in sync any lead originating in the CRM system.
Manually in the Lead Database