The webmaster adds the way to open the right-click Notepad

Click "Start" -> Run -> regedit in the lower left corner to open the registry editor.
Under HKEY_CLASSSES_ROOT → * → Shell, under Shell, the new item is named Open With Notepad++ (note that * is also an item)
on the right side of the new item Create a new string value in the window (right-click--New--String value). Name: Icon; Value: C:\Program Files (x86)\Notepad++\notepad++.exe (PS: installation directory)

 

Create a new item Command (must have this name) under the newly created item Open With Notepad++
Change the default value of the window on the right side of the newly created Command item to: C:\Program Files (x86)\Notepad++\notepad++.exe %1 (PS :installation manual)

 

Effect picture: