Welcome to the Dell Community @MrTushar
Integrated: Intel HD Graphics 520 or Intel HD Graphics 620
Some came with:
Discrete: AMD R5 M430
Inspiron 15 3000 Setup and Specifications:
Sorry no slot/option to upgrade GPU.
Yes man you can always add an external GPU to your laptop. But in that case you will loose your WIFI and Bluetooth Card ( But you can still connect to internet via ethernet cable or a dongle of WIFI Adapter). First check out the WIFI Slot of the device. Maybe for you it is M.2 NGFF Version. If it is this buy an external GPU Dock and a SMPS For heavy power supply along with your graphics card. Now remove all your laptop covers along with your the battery. Now remove the wireless antenna and the wireless card . Now insert the NGFF Card into the slot and the HDMI Cable to the eGPU dock. Now connect the power supply to your Graphics card and install the graphic drivers of the company needed.
Plug in and enjoy.....😃
Another thing if your laptop has an discreet graphics please disable the driver otherwise it could create a problem for your device...
Please refer to the YouTube video dfor more assistance.
Not exactly practical if you want the notebook to serve its purpose of mobile computing, since you turn it into an immobile desktop system with one of these.
If you need better video, leave the notebook as is and purchase a desktop computer - which won't have any of the limitations of an external GPU connected to a notebook that doesn't support one.
You can, but it's still not a practical option - basically taking the time to disassemble the system each time, and reassemble it. Beyond that, notebooks are not designed to be routinely dismantled and reassembled.
These external GPUs are fine for systems designed to take them - such as the Alienwares with the graphics amplifier option. They make little or no sense otherwise - decent eGPUs cost about what a mid-range desktop (new or used) does.