Transfer
Transfer
Usually, you don't.
Your personal files are safe.
Transfer them to another device—flash drive, external HDD, cloud.
Your applications?
A fresh installation in the new OS, in the new system.
You must possess the installation files for applications. Data and game files from the stream can be duplicated. Also, ensure you have an existing backup system that safeguards your information. Essential data should adhere to the 3-2-1 rule. Maintain three copies across at least two physical devices, with one stored off-site to guard against risks like fire, flooding, or theft.
You should be able to link the two computers together and transfer files such as documents and contacts from the older machine to the new one.
Yes, you could too. And if you understood all the details involved, you wouldn't be asking "can I". But it is significantly simpler and more secure to move it to another place and then transfer it to the new system. As previously noted, this ensures a backup copy.
Cloud is a euphemism. It's unclear who came up with it. Likely a marketing team trying hard to stay in the game.
A common name for systems, servers, and services that exist beyond your immediate control. One such example is OneDrive.