Company Structure -> Edit access and details -> Financials

Now by selecting the branch checkbox "Set as default profile", the branch will be used as the default profile for Purchase Orders and Invoices. The profile can be changed from the dropdown list on Purchase Orders and Invoices levels, without the need to change the whole setting.

"Set as default profile" checkbox will be visible only if "Manage Purchase Order and Invoice Profile" is selected. Only one branch can be selected as default.