The <code>date_modify</code>  filter allows you to modify a date by adding or subtracting days, months etc.

For example, if you wanted to generate an invoice ahead of time for a customer in `May 2027`, but the period of service it
covers is `June`, you could put in the item description:

```bash
Service for {{invoice.date|date_modify("+1 month")|date("F Y") }}

This will print "Service for June 2027"
```