Iwould like to import a KMZ o KML file in OSM. IS it posible?
Never used it, but try https://wiki.openstreetmap.org/wiki/JOSM/Plugins/OpenData
You can also convert your KMZ into another format (e.g. GPX) using GPSBabel.
What do you mean by “import”.
As well as the normal required copyright releases, importing data from other sources needs to be cleared with the local community, as it can be very disruptive.
See https://wiki.openstreetmap.org/wiki/Import in the OSM wiki,
but PAY ATTENTION to all hints and rules there about importing data into OSM main database!!!