The "Mg" in your search likely refers to Modular Gulika, a specific font family within the Shree-Lipi NXT software package. These layouts are popular in the Indian publishing and printing industry.
You can find visual guides and layout charts through the following resources: Mg Shree Marathi Keyboard Image
The Mg Shree Marathi Keyboard Image can be easily downloaded and installed on computers and mobile devices. Users can access the keyboard layout through various input methods, including virtual keyboards and keyboard software. The "Mg" in your search likely refers to
Special Modifier Keys (Visible in the Image Legend): Working in a government office or old publishing
Once you find the keyboard layout image, you can use it as a reference to familiarize yourself with the placement of Marathi characters. This can be particularly helpful for learning to type in Marathi.
A → अK → कM → मT → तOnce you have downloaded a reference image (search on Google Images or Bing), you should not just stare at it. You need a strategy.
If you are looking for the keyboard image because you want to replicate the experience on your device, here is a quick guide: