Hello Preeti24,
Welcome to the community!
Most models of android phone would have slightly different menu setups depending on the phone manufacturers. However, you can try to find Settings --> Connections --> Mobile Networks --> Mobile Data. If you still can't find the option to enable data, what phone do you have?
You might also consider verifying whether your APN settings are correct. The proper settings can be found here.
Hope this helps 
Cheers
