Some is trying to access my wife's icloud account what can we do to stop this?

They can't access it without her password. If she thinks that is compromised, she should change it. See: Change your Apple ID password - Apple Support

and also see: If you think your Apple ID has been compromised - Apple Support

A way to increase security of the account is to turn on two-factor authentication: Two-factor authentication for Apple ID - Apple Support

Also note that phishing is common; that includes scam emails about someone accessing the account. They are attempting to get a response of logging into a fake site and divulging the password. See: Recognize and avoid phishing messages, phony support calls, and other scams - Apple Support