You can specify this at the Line and Document levels.

Line level

We recommend that you specify the Buyer at the line level because most payment documents refer to multiple buyers. This is explained in the Croatia (Pymnt): Line-Level Buyer Party topic.

You must include an empty AccountingCustomerParty at the Document level to ensure schema validation.

Document level

If you cannot provide this information at the line level, you can provide it at the Document level.

Example

<ubl:Statement>
    <!-- code omitted for clarity -->
    <!-- Syntactically required -->
    <cac:AccountingCustomerParty/>
    <!-- code omitted for clarity -->
</ubl:Statement>