I bought on the computer but want to install on my Android

[nukecad]

If you have a multi device CCleaner licence it can be used to Activate CCleaner Android.
The Activation Code is your multi-device Licence Key.

See this post (2nd half) which has a link to the step-by-step guide:

CCleaner Pro for Android

If/when you purchase CCleaner for Android through the Google store (or 'Upgrade' from within the app itself) it activates automatically through your Google account. You don't have to download anything extra, you do not get a seperate licence key to input, it's all done by Google Store. CCleaner Pro will be activated on all devices that log into the Google account it was purchased from. If the Pro features are not available in the app then check that you are signed into the correct Goo…