How to lock down an iPad
This video from Bosstab is an excellent resource, otherwise follow the steps below
https://www.youtube.com/watch?v=74-dSttn1sk
Step 1
Enable Guided Access
Open settings.
Go to General and select Accessibility in the list on the right-hand side of the screen.
In Accessibility, scroll right down to the bottom of the featured list until you find Guided Access near the bottom (In the Learning Section).
Toggle the Guided Access switch to “on”.
Tap on Passcode Settings.
Click on Select Guided Access Passcode (this password allows you to enter and exit iPad kiosk mode).
Enter a passcode (you will need to enter it a second time to confirm the code).
You can also opt to use TouchID or FaceID (if it is available on your iPad) to end Guided Access.
Step 2
Configure Guided Access
Open your desired app, we are using safari browser
With your app open, triple click on the home button. The triple click launches, disables and allows you to configure Guided Access when you require. If you’re using the 2018 iPad Pro, triple click the top/side button.
At this stage you are given the option to circle areas on the screen that you want to disable. These areas will then no longer respond to touch. You can circle multiple areas, should you wish.
You can also click “Options” in the bottom left corner. This will bring up a menu of features you can turn on, off and configure, including disabling the whole screen.
Once you have set Guided Access up as you wish, click “Start” in the top right corner. This commences the Guided Access (kiosk) session.
Step 3
Exiting A Guided Access Session
You can exit Guided Access at any time by triple-clicking the Home button (or the top/side button on the 2018 iPad Pro) and enter the Guided Access password to exit. (If you elected FaceID or TouchID, you will need to authorize exit using these methods).