Rich has been scanning an archive of photos from the family history. He's used scanning services, a DIY with Epson Fast Foto, Flatbed scanners. The works. But in the last six months, he's organized the photos and then imported them into Photos. But he can't search by date. The dates have been linked according to the date it's been scanned. Leo says that Photos is using the File modification date. You can't really rely on that.
There is a metadata format called EXIF that will allow you to store important data on the file. Rich needs an app that can modify that EXIF data. Leo recommends Public Space A Better Finder Attributes. It'll not only help you to modify the metadata, but it will prevent the OS from changing the date because it's in the EXIF data, and as such, part of the photo.
It's also batch focused, so you can do tens or even hundreds of files at the same time.
Rich can also use WordStar on his modern mac. There's a project for it called WordTsar
Also a project for using WordPerfect.