Launch Notepad on your system and open a text file in it. Now, go to “ File > Save As.” Or, you can simply press Ctrl + Shift + S keys on your keyboard. This will open the Save As window.

Right-click the HTML file you want to convert. Click "Open With," then click "Notepad." After Notepad and the code loads, click "Save As" to open the dialog window. Type "index.php" in the "File ...