。
She rents out the house furnished.
Literal
She [topic-は] furniture-included [with-で] house [object-を] is-renting-out.
Two practical pieces here. 家具つき ('with furniture, furnished') uses the productive suffix ~つき that attaches to nouns to mean 'with N attached / N-included.' You'll see it in real estate ads (家具家電つき, 'with furniture and appliances'), travel deals (朝食つき, 'breakfast included'), and contracts (ボーナスつき, 'with a bonus'). The verb 貸す ('lend, rent out') means to be on the lending side of the transaction; 借りる is the borrowing side. Add ~ている for the ongoing state: she's currently in the position of renting it out.