What it does
Form 7004 extends the time to file the underlying return by (typically) six months — moving a calendar-year 5472 + pro-forma 1120 from 15 April to 15 October. It does not extend the time to pay any tax owed; for a disregarded entity with no US income tax this is usually not an issue, but confirm with your EA/CPA.
When it must be filed
On or before the original due date of the return being extended. Form 7004 cannot be filed after the deadline to buy a retroactive extension — this is why BorderFile locks out new 7004 purchases once the original date has passed.
How it’s filed
Electronically or by fax/mail depending on the return it extends. For 5472 paired with a pro-forma 1120, we file it by fax alongside the other paperwork and store the confirmation on your filing record.
See also: Form 5472, pro-forma 1120.