How do I record that the rent includes some or all of the bills?

Bills included in the rent sits with the other tenancy terms, and offers council tax, gas, electricity, water and sewerage, broadband or phone, and the TV licence. Leave them all unticked — the default — and the tenant arranges and pays everything themselves.

Whatever you tick changes two clauses of the generated agreement: the tenant's payment obligation, and the statutory written statement of terms. Both then name the bills the rent covers and state that you'll be paying them, instead of the default wording that makes every bill the tenant's own to arrange.

It also drives the Local services section of your tenant's portal, which otherwise points them at their council and their water company to set those accounts up. Anything you've said is included is dropped from that list, so they aren't told to open an account you already hold.

You can change it mid-tenancy from the tenancy page. That records the arrangement as it now stands — it doesn't alter an agreement that has already been signed, which stays as the document both parties put their names to.

Worth knowing: Letting by room? Council tax isn't offered as a choice there. Where each occupier has a tenancy of only part of the property it's a house in multiple occupation for council tax purposes and you're liable as owner, so the room agreement says that outright and your tenant is told the same.