Updating Metadata

If I Adjust Date and Time, or add a Location via the Mac Photos App - will that permanently update the meta data for that given photo? If I then upload the photo to Google Photos, for instance, will it recognize the new date, time and location?

I once updated location, date and time for hundreds of photos I downloaded from Facebook (all of which were missing metadata because Facebook wipes it). Apple then completely revamped the Photos app. I had to redo every single photo. That leads to me to believe that the metadata was not actually updated with each edit. I have put even more work into my photo collection since then, so my hope is that it won't happen again if there is ever a major overhaul or if I decide to switch services