It is sometimes useful to merge many text files into one, for example notes taken on the same topic. Under Windows, all you have to do is go through the command prompt on a current folder, which contains all the files to be merged. A very simple command in this prompt and voila!
Steps

Step 1. Right click the Start menu button (

).
This button (Windows logo) is in the lower left corner of the screen. From the context menu, select File Explorer. For the merger to take place, all the files to be merged will be in the same folder. If they were scattered, you would move them or copy them to one folder.
To be sure to spot them in the merged file, at the end of each of the starting files, leave a blank line or type separators.

Step 2. Open the folder that contains the seed files
In Explorer (right column), click This PC Where Computer. If it is not already the case, make appear, then click on the folder containing your initial files. They should all appear in the right window.

Step 3. Bring up the contextual menu of the right window
On the empty space of this window, hold down the Shift key, then right-click.

Step 4. Click Open Command Window Here
This opens a command prompt in the current folder, where all your files are.
- If the PowerShell interface on Windows was enabled, you should click Open PowerShell window here.

Step 5. At the prompt, type copy *.txt newfile.txt
Replace newfile.txt with whatever name you want to give your merged file, for example mergefile.txt.

Step 6. Validate with the Enter key
The files of the whole folder are then merged into one and this new file is found in the folder concerned.