I use elementary OS but it cant connect to WiFi even when I go to network settings there is no option for WiFi but only Ethernet. Also it doesn't produce sound through the inbuilt speakers of the laptop even when I use the option in settings
If your computer isn't showing WiFi at all, you may need to find a driver for your WiFi card. Do a Google search for your make and model and see if someone has built something or has a solution for it. Ubuntu forums are really helpful for this since Juno is built on 18.04.
Also, sometimes my wifi just stops working and running service network-manager restart in the terminal resets everything and it starts to work.
I'm not sure how to help with the sound issue because mine worked right out of the box, but you might want to approach it the same way you would for your WiFi card.
Depending on the age of your system, Installing the Ubuntu Bionic Beaver hardware enablement stack might help you.
Otherwise try following the troubleshooting wireless on Ubuntu (since elementary OS uses Ubuntu for it's base)
if it is a broadcom card there's a good chance you'll need to install an external driver.