For most of these endeavors, you will 100% need a computer. I highly recommend a desktop with at least 8GB of RAM and a 512GB-1TB SSD.
Digitization is the process of taking something analog (ie: VHS tapes, miniDV tapes, cassette tapes, etc) and re-recording it into a manner that is playable by digital devices such as computers and smartphones.
Lots of people have boxes of old family photographs in their attic. If you can digitize (meaning: scan to a computer-readable file format) them in a timely manner you are providing a valuable service.
3D printing is a rather new market that has a LOT of potential and endless possibilities. You could 3D print your own products, or scan and recreate repair parts, decoration items, accessories, and much more.