Document text
[Date]
[Client name]
Re: Invoice no. [Invoice no.]
Hello,
This is a friendly reminder that invoice no. [Invoice no.] for [Total due] was due on [Due date], and I have not yet received payment.
Please pay by [New date], using [Payment details]. If you have already paid, please send me the details and I will check.
If something is holding up the payment, tell me and we can sort it out.
Thank you,
[Your name]