QuickBooks Online does not eliminate intercompany activity. Here is what people do instead.
The search that brought you here usually starts with a combined P&L that is too big. Company A billed Company B, both sides recorded it, and the group now shows revenue it never earned. This page is the straight answer: what QuickBooks Online offers for that, what Intuit itself recommends, and where the automated version of this feature actually lives in Intuit's lineup.
What Intuit recommends you do
Intuit's own article on intercompany transactions describes the manual method: each entity records its side of the transaction, one as a receivable and the other as a payable, through a dedicated clearing account for each entity pair, and you must eliminate those activities during consolidation. That is accurate and it is also the whole problem. In separate QuickBooks Online files it means:
QuickBooks blog, "Intercompany transactions: best practices for multi-entity accounting", verified
Where the automated feature actually lives
Intuit does ship intercompany eliminations. The help article that explains them applies to Intuit Enterprise Suite: for each company you choose the accounts used solely for intercompany activity, and the eliminations remove those transactions and balances from consolidated reports. It is a different product from QuickBooks Online, custom-quoted, and independent estimates put multi-entity deployments at $12,000 to $15,000 a year before implementation. Spreadsheet Sync on QuickBooks Online Advanced combines companies into a spreadsheet; Intuit's article on it does not address eliminations.
Eliminations as a property of the ledger
Nummio approaches this from the posting side rather than the reporting side. An intercompany entry posts both sides in one transaction or neither posts, so the reciprocal Due to and Due from balances between any two entities net to zero at all times, by construction, and a property test proves it. Because the link between the two sides is recorded, the combined and consolidated statements eliminate against it at report time without adjusting either entity's books, and the close checklist reports the intercompany reconciliation as a line item rather than a hunt. Watch a paired entry post and the combined statement eliminate it, and read why combined and consolidated are different words.
The concession: this requires both entities to be in Nummio, and the migration of several QuickBooks files is proven per file by two reports. What that portfolio costs on each stack is on the calculator.
See both sides post at once.
The intercompany demo runs the real posting engine and the real elimination, in your browser.