Indoor cycle is missing from the workouts on my Apple Watch
Yes, Indoor Cycling is missing from the activities list when adding a workout.
[Re-Titled by Moderator]
If you are trying this on the Apple Watch, there is a button in the fitness app called ad a workout where you can find countless workouts.
If you are trying to manually log your workouts from the health app on your iPhone or iPad, just select the ,,Cycling" workout. I also sometimes log my workouts manually if I forgot my Apple Watch and therefore noticed it. It is not a big deal though. What counts are your burned calories and exercise minutes that it adds to your rings.