As file and folder names can be up to 250 characters in length they can be used for other things other than just naming files and folders. They can be used for basically short notes.
So rather than having to open an application to create some text, you can just create a file or folder and type in something to remind you of something.
As an example. I went through a large number of photos and renamed them to give them a meaningful name. There were thousands of photos in many many folders. I've been doing this for a number of months and to be able to a record where I am up to in each folder and within each folder I just created one file called AAA renamed up to file, followed by the name of the file.
On a Windows computer you can create a new file just by right clicking and selecting new and then the type of file. I usually use text files, that way I can type some text into it should I need to. But as described I usually don't.
On a Windows computer you can create a desktop file or folder and give it a name to remind you of something. On a phone you can create a file name and have it shown on the home screen to remind you of something.
If you don't understand any of this or know how to work with files and folders, contact me