Updating Exif Data on JPEG Pictures

I have all these pictures and more are coming.  I am concerned about 20 or 40 years from now when we look at them and say "who was that?".

I feel the solution is to update the Exif data which is embedded in the picture.  I have been trying to find a way to update the Exif data.  Windows 10 and  and Mac OS have the ability built in.  I am still working on a way to update it in Android and IOS using a web page.

To update it on Windows 10, right click the picture, select properties.  Click on the Details tab.  The first section is editable.  Most of the other parts are not.  Below you will see that the Apple Title and Description are correlated to the Windows Title and Description.

On MacOS, I found you can modify the Exif data by opening the picture in the Photos app and running Command-I that will show the following screen which will allow you to update the Title and Description by clicking on the line you want to change.

You can also use TheXifer to change these and many more Exif fields.  It is free for a limited amount of photos per day.  You can link it to your Dropbox, Flikr and Google Drive accounts but I am concerned about security risks.  You have to assume that they keep any photo you upload but I doubt they spend much time figuring out how to exploit the photos on an individual basis.

I am working on a small VM to update a limited number of fields by a web page that uploads the file, changes the fields and then downloads the file again.  Using PHP does not seem to be an easy way to make the change.  This is a portable, watered down version of TheXifer.

Dry(er) information:
The Exif data is written in accordance with an Adobe standard called XMP.  It was later adopted in ISO 16684-1:2012 which has been updated.

If you add a title or description and then edit the JPG with an editor such as Notepad++, you can see the data in several places under XML tags and in binary portions of the file.