Canon EOS-1D X Mark III Advanced User's Manual page 660

Registering IPTC Information
Enables you to edit and register IPTC* information (comments on images, such as captions,
credits, and shooting locations) on the camera. Images can be tagged with IPTC information
registered on the camera.
* International Press Telecommunications Council
1.
Select [IPTC info].
2.
Select [Load from file].
A screen for editing IPTC information is displayed.
Selecting [Load from file] enables you to load IPTC information (in
XMP format) that was saved using EOS Utility.
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