A yellow padlock marks a feature that is not in your current plan. Upgrade your plan to use it.
The padlock is about your plan, not your staff role. A page your role cannot open is not in your side menu at all, and a settings page you can only view shows You can view these settings, but your role can't change them.
A locked page shows in the side menu in amber, with a padlock beside it.
Step 2. Find it in your settings
A tab in Settings & Configurations can carry the same padlock.
Step 3. Open the locked feature
Press the locked page or tab. You see This feature is not available on your current plan. Upgrade to unlock it.
A locked button opens the same message in a window.
Step 4. Press Upgrade Now
Press Upgrade Now. The Subscription Plan page opens with your Current Plan and the plans you can move to. Opening it charges nothing. You pay only after you choose a plan and confirm.
Step 5. Choose a higher plan
Press Upgrade on the plan you want, then pay.
Result
The padlock is gone and the feature is ready to use.