Hi @Alicia
We use a little thing called CSS Transformations. It involves putting a few lines in your invoice style CSS to change a specific label.
There’s more details, including a “map” of the fields, here: CSS transformations
The “Purchase Ref” specifically, is .transform-invLabel_03
. This can be used like this:
.transform-invLabel_03 {
content: "New Label";
}