This post will show you how to screenshot your Mozilla fire and Google chrome web on your PC.
On Firefox
Visit the Mozilla Firefox add-on page and select extention at the top and on the add-on search bar, search for Lightshot (screenshot tool).
Click on “Add to Firefox”

Grant the extention the requested access to your device by click Add at the top right pop-up dialouge box.
To screencapture with lightshot, lookout for the extension icon at the top right side of your firefox, incase you can’t find the icon tap on the three bar at top right corner and select ‘Add-ons and themes’

select lightshot screenshot from the light of the extension when you are on the page you want to capture, it will prompt you to select the area of the page you intent to capture the screen
On Chrome Browser
Visit the Chrome webstore
Follow the same steps for Firefox browser to install and use the extension.