To enable Apple Health, please check the following settings.
1. Open the Insight Timer app.
2. Select your Profile icon located in the upper right.
3. Click Settings (gear icon) on the upper right corner.
4. Scroll down to Apple Health.
5. Toggle on 'Apple Health Mindful Minutes'.
Then, Launch iOS settings.
1. Select Privacy
2. Click Health
3. Ensure Insight Timer is selected.
If you still don't see the Insight Timer app in the Health section under your iOS settings, please log out of the app, reboot your device and log in again.
You may also want to ensure your iOS software is up to date.