How do I get rid of this item in my menu bar on macOS
To uninstall the Citrix Receiver for Mac, open the
  CitrixReceiver.dmg file and select Uninstall Citrix Receiver.
  
  After uninstalling the Receiver and rebooting the system, ensure
  that the files or folders listed in this section have been removed
  from your system. If they still exist, remove them manually.
  
  /Applications
  
  
  Citrix Receiver.app
  
  
  /Library
  
  
  /Internet plug-ins/CitrixICAClientPlugIn.plugin
  /LaunchAgents/com.citrix.AuthManager_Mac.plist
  /LaunchAgents/com.citrix.ServiceRecords.plist
  
  
  /Users/Shared
  
  
  /Citrix/Receiver Integration (entire folder)
  
  
  ~/Library
  
  
  /Internet plug-ins/CitrixICAClientPlugIn.plugin
  /Application Support/Citrix Receiver
  
  
  CitrixID
  Config
  Module
  
  /Preferences/com.citrix.receiver.nomas.plist
  /Preferences/com.citrix.receiver.nomas.plist.lockfile
  /Preferences/com.citrix.ReceiverFTU.AccountRecords.plist (added in 11.6)
  /Preferences/com.citrix.ReceiverFTU.AccountRecords.plist.lockfile (added in 11.6)
  
  
  ~/Applications
  
  
  Under this folder, you can delete any applications you previously added via the Receiver UI.
  
  
  /private/var/db/receipts
  
  
  com.citrix.ICAClient.bom
  com.citrix.ICAClient.plist
  


To get to some of these locations faster using Finder, hit Command+Shift+G (or use menu Go > Go to Folder...) and paste the location there.

More info on the Citrix website.