If you want support for Myanmar in your PowerPoint application, then you must know that a font is necessary to be installed on your PC. For example, if you open a file that has text added using Myanmar font, PowerPoint will display some dots and squares.
Look on Google for a Myanmar font and then to Start > Run > Fonts. Drag and drop al the fonts you have into that folder, reboot the PC and then you can use PowerPoint to insert Myanmar text.
You can download fonts through Google Search: https://goo.gl/pFruPT