I have a licence for CCleaner Pro and want to add a second PC to the licence - is this possible please?
Your best option is almost certainly to upgrade to Pro Plus which cover 3 devices.
If you contact support they will be able to give you upgrade options and prices. (Sometimes there are special offers on for existing users).
It will be much cheaper than just buying a second licence and having 2 different ones.
The time remaining on your existing licence will be added to the upgraded Pro Plus licence.
Email them and explain what it is that you want to do, just like you have above: support@ccleaner.com