I have created a custom button on the detail page of the event object and passed the record id in the URL but I'm not able to get the get that id in the LWC component as you can see in the screenshots. please guide me on this how to get the record id so that I will be able to display the event object fields to update by the user.
You should be able to have record Id in
recordIdvariable in js file. Check this Trailhead - https://trailhead.salesforce.com/content/learn/projects/lwc-build-flexible-apps/single-record . You should have
<targets> <target>lightning__RecordPage</target> </targets>
in your js-meta.xml file. Then in js file you have
@api recordId;and record Id magicaly apear there.