Is it possible for me to underclock my CPU?

a couple of things go into the heat of the CPU, 1. voltage 2. core clock, 3. cooler, 4. thermal paste, 5. airflow.

make sure your not over volting the CPU,
make sure your cooler is clean (remove the dust bunnies)
make sure your cooler fan is spinning properly
make sure there is plenty of airflow.
make sure the HT/base clock is correctly set to default.

in the bios make sure the multiplier is set correctly. if it is raised it will OC the CPU. to underclock the CPU you would lower it.

If all is set correctly then look into reseating the cooler on the CPU.

The CPU will run only as fast as the system demands - you can use the power management settings to control the CPU speed.

Unless the system is running abnormally hot -- in which case a thorough internal cleanout and replacement of the thermal pad will do more than limiting the CPU speed -- this system is best left alone and in its default power management scheme.

Inspiron 14-3467 

Yes Underclocking and Undervaluing helps , but you have to have powerful enough CPU/GPU to pull down it's performance. Benefits are Better battery and Cooling

Your machine doesn't need it. It simply Doesn't 

You can make following changes to reduce CPU usages though 

From Battery Icon from bottom right side you can move the slider towards battery saver 

From BIOS (F2) > performance > you can turn off Intel Turbo Boost. 

You can install Dell power manager from windows store and choose silent profile. 

So does that mean I can underclock my CPU by going to the bios?