High grade fever with chills
may be due to infection( bacterial, parasitic or viral).
For controlling temperature give her paracetamol
6 hourly. You can use ibuprofen
or mefenemic acid if paracetamol fails. Also do tepid sponging this is very effective method to reduce the temperature.
Don't get panic you can wait for two hours by following above if there is no other symptoms( like altered sensorium, breathing difficulty etc.). Give her plenty of fluids this will help in management of temperature. Blood test
and urine test may be needed to find out the cause of fever.