I have a CSV file with lat and long coordinates, is there a way I can convert it into a shapefile so as to generate a mobile network coverage map like the AT&T image I have attached.
If you don't have a 3D Analyst license, you can do this:
Add the CSV file to ArcMap, right-click on it and select Display XY data. Select appropriate values in the shown dialog, press OK. A new featureclass will be added to the map. Right-click on that, select Data, Export Data.
Alternatively, in ArcCatalog, right-click on the CSV file, select Create Featureclass, From XY table.
What about to use ASCII 3D to feature class tool? If your point doesn't have Z value, you could use for Z value for expample value 1. I assume you have only X and Y values.