Odoo 8 - 如何更改div class =“page”中的内容

i have Odoo 8 and i trying to edit content of template of invoice/order and more. I managed for now to change the header and footer entering in external_layout and external_layout_header/footer (From backend of Odoo). But i don't know how change content of div class="page".i have Odoo 8 and i trying to edit content of t