How can i turn mobile data on without going into the settings?
There is no specific way to turn off only Cellular Data without going into settings.  A (possibly) quicker work around for you would be swiping up from the bottom to get the control center, then turning on Airplane Mode (far left button) and then turning back on WiFi and/or bluetooth.  

That would disable cellular data,WiFi, Bluetooth by going into Airplane Mode, and you would get data over WiFi back when you turn that back on.