My apple music doesn’t have cancel subscription option. How can I cancel it?

See instructions in How to cancel a subscription from Apple - Apple Support or use an internet browser to cancel as described in How to cancel Apple Music - Apple Support

Also see the following from How to cancel a subscription from Apple - Apple Support

If you don’t see Cancel, the subscription is already canceled and won't renew.

and

If you cancel a paid subscription, you can keep using the subscription until the next billing date.

Also, a subscription that is already cancelled will typically have wording in fine print similar to "Expires on [date]" rather than "Renews on [date].”