Along with each photo exported from Lightroom some amount of metadata (i.e. data about you and your photo) is also written into each exported copy. What data is included is dependent upon what data you applied to your photo while in Lightroom (such as your copyright information, contact information, titles, keywords, etc.) as well as what choices you make on the Export dialog.
There isn’t a right or wrong answer as to what to include in your metadata during export. What matters is what is required for the given job at hand. In some cases you might want to include every possible bit of data and in other cases you might want to exclude certain data. I just want to make you aware of what is possible.
All of the options for controlling what is included can be found on the Export dialog in the Metadata section (scroll down if you don’t see it). We even got a new option with Lightroom Classic. Click the Include drop-down menu to see what’s available. Note, when exporting DNG or Original file types, All Metadata is used and this is not possible to change. The other Include options only apply to JPG, TIF, and PSD exports.
At the top of the list is Copyright Only, and this prevents Lightroom from writing anything more than what you’ve included in the IPTC Copyright section of the metadata template (or added manually in the relevant fields of the Metadata panel).
Next is Copyright