how do i delete “try apple news for free” from my calander?

Go to Settings > Passwords & Accounts, and check what accounts you use with Calendar app. It's possible you have added account/subscription that sends you spam in Calendar app.

If account is there but you don't see "Remove" button, that account possibly was added using configuration profile.

Go to Settings > General and scroll to the bottom. Look for section called Profiles, tap on it, tap on the installed profile and delete it.

It is also possible that you got spam through the account you use with Calendar.

If you use iCloud Calendar report the issue with spam to Apple per instructions found here: https://support.apple.com/en-ie/guide/icloud/mm170ca648c3/icloud

If your Calendar is hosted by Google, Yahoo, Outlook or someone else, check their documentation how to deal with spam junk calendar events.