A customer does not pay invoice

I have a customer who does not want to pay the sent invoice.
How do I book this in Manager.IO

kind regards,
Jan

Since you emitted the invoice you already booked it. If you want to move to a new category, ie “unlikely to pay”, you can create a control account and move the customer to this new one.

Last, if you agee that he shouldn’t pay you should issue a credit note.

As @Davide wrote, if you agree the customer should not pay for some reason, such as defective merchandise, issue a credit note. See this Guide: Use credit notes for customer returns and refunds | Manager.

If the customer refuses to pay a legitimate invoice, you should write off the bad debt. See this Guide: Write off bad debts | Manager.