Download the plugin from wordpress.org/plugins/convertkit
Go to your WordPress site and click on “Plugins” in the left-hand dashboard
Click “Add new”
Then click “Upload plugin”
Upload wp-convertkit to the /wp-content/plugins/ directory
Activate the plugin through the “Plugins” menu in the dashboard.
Go to the Settings page by clicking on the link under the ConvertKit plugin.
Enter your ConvertKit API key. Click save.
Select your default form. Click save.
Optional: If you’re using more than one form, set specific forms for each post or page by visiting the Edit screen and selecting the correct form