AirPrint from iPhone and change Paper Size
iPhone 12 Pro with HP Deskjet Printer 3830 with Airprint.
Please check the pic below which is self-explanatory and will work depending on the printer model that you have.
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Community members who reach Level 5 in the community can create User Tips to share knowledge about Apple products. Check out this User Tip created by Lawrence Finch: When to charge your iPhone or iPad
Community members who reach Level 5 in the community can create User Tips to share knowledge about Apple products. Check out this User Tip created by Lawrence Finch: When to charge your iPhone or iPad