To send a billing document through EDI or IDOC in SAP, follow these steps:

1️⃣ Set up partner profiles: Define communication partners' system, port, and parameters.
2️⃣ Create output type: Define an output type for the billing document and assign it to the relevant partner function.
3️⃣ Configure message control: Define the message control settings for the output type, specifying EDI or IDOC transmission method.
4️⃣ Determine partner: Configure the partner determination procedure to determine the partner responsible for receiving the billing document.
5️⃣ Test and monitor: Perform testing to ensure successful transmission and receipt of billing documents via EDI or IDOC.