I currently use LR 5.7 and PS CS6 on 2 PCs
If I sign up for Creative Cloud Photography, how many PCs can I install on with a single membership (I have a desktop and a laptop).
Can I also install on my phone and tablet?
To check What’s included with the Creative Cloud Photography plan refer Lightroom and Photoshop | Adobe Creative Cloud Photography plan
For number of devices kindly refer Licensing FAQ: Can I install Creative Cloud on more than one computer?
You may also refer Creative Cloud Help | Creative Cloud / Common Questions
Hope it helps !!