It takes the same amount of ink to print regardless of whether you do it yourself or if someone else does it. You can also just store it in its original digital form. Put it on your hard drive, or an external drive, or on magnetic tape, or on the cloud, or anywhere else.

A hash is any kind of mapping from the raw data into a fixed length piece of data. This is usually preferable when you don’t want to store the actual data but you want to be able to verify with some degree of certainty that the data hasn’t changed. As an example, for tabular data, you can hash each column by computing the mean. If the data changes, then that mean will likely change too.