Q: Change settings remotely

If you have Find my iPad turned on in iCloud and the device, you could lock it.  However, you cannot turn it on after it is out of your hands.

Have a nice day.

"I left my iPad at my friends house and I do not want them to see my notifications"

Translation:

"I left my iPad at my Girlfriends house and I do not want her to see all my ****" 

No, you can lock it remotely, place it in lost mode or erase it.  That's it.  There is nothing else that can be done to an iPhone or iPad remotely.  The only way to access the device settings is to have the device in your hands.

When you have it back, add a hard to guess 6 digit passcode.