Templates for invoices, receipts, badges and more exist in the Operations app > Reports module > Communications tab.
Invoices
Your Invoice templates will be of the Invoices Email type. The default version is titled Billing Invoice. After clicking the edit pencil you will see the email version and the PDF version of this template are managed in separate tabs. Here, most of the template will exist in the "body" editor field, while the individual line items will be created in the "item" editor field, then embedded into the "body" editor field. You can use the tags available in the toolbars of each editor field to add in dynamic content such as the contact's name, email, balance, etc.
The receipt templates will also be of the Invoices Email type. The default version if titled Billing Payment and works very similarly to the Invoices Email template.
Badges
Badge templates will be of the Contact Database PDF type. This template also uses a body-repeat-item structure. The Body editor needs a [[repeat]] tag and the Repeat editor needs a [[item]] tab. The item can be just about anything but the default can be added by clicking the "Copy Default Template" button.
Badges can then be printed by going to the Contact Database module, selecting one or more rows, then opening the Action dropdown and selecting "print".
Please submit a support request if you have any questions.