Host your MailChimp capture form on your WordPress site as widgets or as standalone forms on individual posts.
The main purpose of BigMailChimp plugin is to enable the user to host their MailChimp capture forms on their own website without the need to write a single line of code. Moreover, you can display your capture forms as widgets or as standalone forms on individual posts. Simply create/modify your forms on MailChimp and the changes will take effect on your site instantly.
Form more information visit the plugin's page