If your existing site has forms, submissions and email notifications from Solspace Freeform v3, it can be easily migrated over to Formie. Your existing content with Freeform will not be touched.
To migrate your forms and form data, install Formie, and navigate to Formie → Settings → Migrations → Freeform.
You'll be shown a screen to select from any existing Freeform forms. Select which ones you want to migrate, and hit "Migrate Forms". The next screen will show you the result of the migration, detailing what forms, email notifications and submissions were copied across and what errors or exceptions were encountered.
Any form that is attempted to be imported with the same handle will have a number affixed to the form. So if you already have a Formie form with a handle
contactForm and also have a
contactForm in Freeform, the migration tool will name this new form to
The following Freeform fields are currently unsupported in Formie:
Available for Craft 3. Get it from the plugin store.