how to export the journeys in kml

Hello,
how to export the journeys in kml ? when I export it comes to excel.
I have installl traccar 6.0

Use this API endpoint:

GET /api/positions/kml?deviceId=x&from=x&to=x

please which file should I modify to add? the traccar.xml file?

You don't need to modify any files. It's enabled by default.

in this case how to use it to get kml file?

I already said how.