Messenger Checkbox Plugin
Include the checkbox plugin in forms on your website to allow people to opt-in to receive messages from you on Messenger. This is useful for following up at a later time for promotional or non-promotional purposes. This plugin only works in HTTPS websites.
To add the checkbox plugin to a form on your website:
Step 1: Under 'Messenger Tools' in the sidebar select 'Messenger Bot'.
Step 2: Click on 'Actions' under 'Messenger Engagement'.
Step 3: Select 'Checkbox Plugin'
Step 4: Click 'Create Plugin'.
Step 5: Select the page associated with the plugin, add your domain, select a confirmation message template, and add a reference tag.
Step 6: Adjust any additional settings as required and click 'Generate Embed Code'.
Step 7: Copy the generated code and add it in the desired html element on your webpage where you want to display the plugin.