In certain cases you will need to activate system settings on your child's phone, e.g. formatting SD card, switching off mobile data, etc. You activate access to full system settings from your parent app.
1. Open parent app
2. Swipe up on the child card
3. Click top left corner (three dots)
4. Choose Child Settings
5. Toggle on Grant access to full settings for an hour
6. Click check mark in top right corner
Now go to child phone, click top left corner, and in the menu system settings will now appear.