How do I label photos with names, dates, places, etc?

You can use Titles, Keywords and Comments to do what you want. This user tip describes more: For what purpose should we use Titles, Keywords, caption - Apple Community

For locations, if you bring up the Info pane for a photo in the library and enter the GPS coordinates of where the photo was taken it will bind it to that location. You can get the coordinates via Google Maps. Or give a name, city & street, park name, building name (like the Empire building) and it will show the location in the small map of the Info pane. Gone are the days where we could locate the location on the map by dropping a pin and then giving it our name for that location, i.e. Toad Hall my home.

Hi LeahLizzie,

To edit a photo's date and time or remove the location in the Photos app on a Mac, you would do it in the information panel by following Add titles, captions, and more to photos using Photos on Mac.

Take care.

I am not sure, what you want to achieve? Do you want to add dates and locations internally in the Photos Library, so the photos are easier to retrieve? Or do you want to write the captions as text into the photos, so the people you share the photos with can see the date and location as a text written into the photo?

To write text into the photo you can use the Markup extension in Photos. This is described here in the Photos user guide:

Write or draw on a photo