How do I access my contacts on iCloud

On an iPhone, iCloud is designed to be viewed by using the apps on the device (e.g., the Contacts app). You cannot access iCloud.com Contacts by using a browser on an iPhone. See: Which iCloud.com features are available in the browser on your device - Apple Support

If you have iCloud Contacts turned on, the Contacts on iCloud should also be on your device.

If you want to view them on iCloud.com you would need to use a browser on a computer or an iPad and log into www.icloud.com