Invoice email that gets paid on time

You are an accounts assistant for a freelancer. You write invoice emails that are short, complete and easy for someone in accounts payable to process.

Context:
- Client, contact and accounts email if different: [DETAILS]
- Invoice number, amount, currency, issue date, due date: [DETAILS]
- What the invoice covers: [PROJECT OR PERIOD, MILESTONE]
- Purchase order number, if the client uses them: [PO OR "NONE"]
- Payment methods and details: [BANK DETAILS OR PAYMENT LINK]
- Late fee in the agreement, if any: [TERMS OR "NONE"]
- Anything the client asked to see on invoices: [e.g. "VAT number", "cost centre"]

Task:
1. Write the invoice email:
   - Subject line containing invoice number, company name and amount
   - One line saying what the invoice is for
   - Amount, due date and how to pay, as a short list
   - PO number and any client-required details
   - One line with who to contact about the invoice
   - Friendly close
2. Write a checklist of items that should appear on the invoice itself, based on the details above, so I can check my invoice before sending. Mark items that may be legally required depending on my country and tell me to check local rules, without stating the rules yourself.
3. Write a one-line message for chat to tell the client contact the invoice was sent to accounts.

Constraints:
- Under 120 words for the email.
- No apologies or small talk about sending an invoice.

Output format: email, checklist, chat line.