how can I move my music from one iCloud account (old iPad2) to another (new IPadv8)?

If you are using the same Apple ID on the new iPad, and you should do that, you can transfer the contents of the old iPad to the new iPad and the music will download as well as your apps and other purchased content, once you set up the device.

Choose the method that works best for you.

Transfer data from your previous iOS device to your new iPhone, iPad, or iPod touch - Apple Support