Is it possible to transfer blockchain data from one machine to another? I want to run a bitcoin full node at home but the initial sync-up is taking days because of my slow internet connection. Can I download the blockchain data from a machine with faster connection and transfer over to my home machine? Is this possible and if yes, how?
You can simply copy the entire data directory from an existing bitcoin-core installation on another machine over to your machine, then start the bitcoind daemon.

Be aware you'll want to create a backup of the wallet.dat file from the destination machine so you don't inadvertently overwrite it.  You may also want to confirm the bitcoin.conf settings work for the destination machine.  Specifically, you may want to modify the rpcpassword, memory configuration, etc.

On Windows, the data folder is installed by default into %AppData%\Bitcoin