There are several ways that you can convert the LED TV to a smart TV. The first way is to have a portable media player.
Chromecast is one of the trendy portable media players. Chromecast comes with a micro USB port that you have to connect to the USB port of your LED TV.
Then switch to the HDMI source and follow the setup instruction. Then download the Chromecast app on your smartphone and connect to the same wireless network.
Now run the app to follow the instructions to link your LED TV to the adapter. After completing the process, your LED TV will be converted to a smart TV.
Apart from portable media players, you can use Amazon FireTV stick, box type media players, and Apple TV network media player to convert your LED TV to the smart TV.