Hi @chgreen,
You can change the data in your header (logo, shop address) via the plugin settings: WooCommerce > PDF Invoices > General
Please note that most changes made to the invoice will only be reflected in newly created invoices after you made the changes. This is because in most countries the invoice should be immutable after issuing. However you can overwrite this for old invoices by temporary enabling the ‘Always use most current settings’ option via WooCommerce > PDF Invoices > Documents > Invoice