We will need more information: The exact model number.  Most G15 released after 2020 have Display port over type C support, but again I will need your model number to give you exact info. You can also find user manual of your copmputer from support.dell.com (enter service tag) : Documentations > Setup and Specifications   You will land on a page like this and check yourself.      Now if your model has a supported type C port. WD19S would be a perfect dock for you.  Again I will need more info about the exact model and the resolutions of the monitor you are planning to connect   
I am looking to buy a Dell Inspiron G15 laptop and would like to know if I can connect it to my WD19s docking station to run 2 external screens, but provide power to the laptop through its intended power supply?
Can I use my use my WD19s docking station with a Dell Inspiron G15 to run 
external screens