Every time I plug my laptop to charging point and connect to wifi this starts to use 98% cpu for why?? see in the given screenshot i didn't even started firefox still its using CPU resources

here is screenshot for same

You may have a malware infection running a hidden instance of Firefox. This support article lists cleaning tools that other Firefox users have found successful:

Troubleshoot Firefox issues caused by malware

Run most or all of the listed free to use malware scanners. Each works differently. If one program misses something, another may pick it up.