Open Registry Editor by pressing Win + R, typing regedit, and pressing Enter
Go to HKEY_CLASSES_ROOT*shell
Right-click shell, select New, then Key
Name the key after your program
Set the default value of the key to the menu text you want to see
Right-click the program key, select New, then Key
Name the new key command
Double-click the default value inside command
Enter the full path to the program executable in quotes
Add %1 after the executable path if you want the selected file to be passed to the program
Example: “C:PathToProgram.exe” “%1”
Close Registry Editor
Right-click a file to see the new menu item
To add it for folders, use HKEY_CLASSES_ROOTDirectoryshell
To add it for all files, use HKEY_CLASSES_ROOT*shell
To add it for background right-click in a folder, use HKEY_CLASSES_ROOTDirectoryBackgroundshell
Restart File Explorer if the menu item does not appear immediately