Hello PodGui,
Thanks for reaching out to the Apple Support Communities! I understand that you're looking for a way to change the activity level for your Apple Watch.
If your Apple Watch was running an older version of the watchOS, you would've seen Lightly, Moderately, or Highly under the Daily Move Goal screen. This sets the daily caloric move goal based on how active you are, or how active you'd like to be.
You can find this information from the "Get started," section of this article: Track daily activity with Apple Watch.
"When you set up your Apple Watch, you’re asked if you’d like to configure the Activity app. If you choose not to, you can do so later when you open the Activity app for the first time.
- Open the Activity app
on your Apple Watch. - Swipe left to read the Move, Exercise, and Stand descriptions, then tap Get Started.
- Use the Digital Crown to set your sex, age, height, weight, and whether you use a wheelchair.
- Choose an activity level and start moving."
You can only choose the activity level during setup. After setup, you can only make adjustments to the Move Goal: Use the Activity app on your Apple Watch.
If you don't want to manually make an adjustment to the Move Goal, check out this information:
"Calibrating your watch can also help it learn your fitness level and stride, which improves accuracy when GPS is limited or unavailable."
This article will show: Calibrating your Apple Watch for improved Workout and Activity accuracy.
All the best!