How do I check the MailChimp subscribe input box by default?
First, it's important to note this is NOT recommended. Users should opt into a list on their own accord so this goes against MailChimp policy.
To use this snippet:
Simply add this to your WordPress theme before the closing body tag (</body>) and reslurp it. Or you can add it in the HTML Editor in your Cloud Dashboard. Its also important to note, if you have multiple lists, this snippet will check every list.
Here is where you can find it in your Cloud Dashboard:
As seen here: