A family of Microsoft word processing software products for creating web, email, and print documents.
Custom sizes depend in part on your printer driver being able to handle custom sizes. Not all can do it. For help with your printer driver, you'll have to query HP Support. This reply doesn't cover the steps to set that up.
Assuming your printer driver can use it, here's how to create a custom page size in macOS Ventura:
- In Word, choose File>Page Setup.
- Change the Paper Size dropdown to Manage Custom Sizes.
- In the dialog that opens, click on the plus sign to create a new custom page size. Double-click on the Untitled name and change it to A2 or A7.
- In the Width and Height fields, enter the page sizes. Printer drivers always assume portrait page orientation, which is counter-intuitive for an envelope. Enter the smaller dimension in Width, the longer in in Height.
- Enter the minimum margins your printer model can print.
- Click on OK.
- Back in the Page Setup dialog, your custom size should be selected in the Page Size dialog. Change Orientation to Landscape. Click on OK. Word sets the page size to your custom size.
Assuming you can create the same size in your printer driver, you should be ready to go.