I can't use iCloud for backing up data from third party apps

I'm using an iPod touch 6th gen and I wanted to use iCloud to back up data from Twitter, IG, Pinterest etc. I tried searching for steps. So far I've been finding the same set of instructions:

Settings>iCloud>Storage>Select your iDevice>Turn on apps you want iCloud to back up

But after clicking Storage I only see "Manage Storage" and under that, the option to "Change Plan." How come my iPod doesn't have the option to choose iDevice? I can see the option to back up data from built in apps, but not from third party apps. My iCloud Drive is on but my Photos under icloud is turned off. I really need the extra space. What seems to be the problem?