Set how many days before contract expiry to get notification. The notification is only visible to staff members that have permissions Manage Contracts or is Admin.
Notifications wont be shown on clients side.
You can set contract notifications by going on Setup -> Settings -> Cron Job -> Contracts.
If contract is expired the list table row will be filled with red background.
You have option to receive contracts expiry notifications additionaly to email. Check the email template from Setup-> Email templates.
If you dont want to receive emails for contract expiration notification you only need to disable this email template.