On the hodl hodl platform you open a trade to sell bitcoins to an existing Buy advertisement for the amount of the invoice you want to pay. When you are asked to provide the payment details, you give the details to pay the invoice. Buyer pays. The person expecting the invoice to be paid confirms the received payment. You release the bitcoins. You can do the same without the escrow offered by the platform with buyers you know personally and trust. I pay rents, professional services and other stuff this way, in countries where I don’t have a bank account.