Notepad++ is a great text editor that can do a lot of things.
Instructions to set Notepad++ as your default text editor
Run Notepad++ as admin
Settings > Preferences > File Association, select Notepad.
Move the .txt and .log extensions to Registered extensions
If you like to add JSON as well, click custom and type .JSON (or any other extention)
Close the dialogue, close Notepad++.
Right-click on any .txt file > Open with… > select Notepad++