I have created a footprint that I can see in the project files when I’m at the KiCad 7.0 “home page”. When I click on it it is displayed as I created it (42 pin DIP) and I see it in the list of symbols that drops down when in schematic and one clicks on Place and then Symbols. But it never appears so I can’t click on it and add it to my schematic.
In KiCad, Symbols are the symbolic representations of parts in the schematic, and Footprints are the things you put on the PCB with real life dimensions and which define the pads, silkscreen (a.k.a. legend) and such. You are mixing up the two terms in your post and it is not clear what you actually mean. But the answer is very much the same. You need to put them in a library, and the library has to be added to the library table (Either global or project specific) before you can use them in KiCad.
In any symbol list you should see only symbols, not footprints.
You not add footprint to schematic.
At schematic you have symbols and then footprints are assigned to symbols so when you move from schematic to PCB the right footprints are used there.