If you sign up for Zoho One but you still receive a notice of your 14 Day Trial in Zoho CRM then it may mean that you signed up for a trial of CRM BEFORE signing up for Zoho One. This sometimes causes some confusion but can be fixed easily.

Open https://one.zoho.com/ and click Admin Panel, then click Applications and search for the app that has the "14 Day Trial" message. When you click on the app there will be an option to add that app to your Zoho One. Once the app has been added the message will disappear.