Navigation → Documents → Processing → Customer Invoices → Select Multiple Customer Invoices from List
You can select multiple lines by holding Ctrl whilst selecting the desired documents by clicking on them. This applies to Credit Notes, Goods Received Notes, Supplier Invoices and Returns To Supplier documents aswell.
On top tool bar select the Post Bulk Invoices
icon or click Processing on top menu and select Post Bulk Invoices.
All the selected documents will be Posted to Financials.