The methods by which 4K movies are distributed come in different forms, as they must be adapted to suit equipment and tastes. They can be roughly divided between those that you can keep at home, either on a UHD Blu-Ray disc or external memory stick, and those that you must watch directly from the internet.
Disc: If you've ever watched movies from a disc, then you know how convenient it is to just put it in the player and enjoy it. In this case only Ultra HD Blu-ray discs are capable of playing 4K content, although you will usually find them on the market simply called "4K".
Digital file: When we talk about a digital file, we mean one that can be stored in the memory of computers, smart devices and USB sticks. This is the one you would look for if you don't care much about discs as they will save space on your shelves, but not so much on your computer as they are very heavy files.
Streaming: If you've watched a series on Netflix or videos on YouTube you know how it works. Movies are played as they are downloaded from the internet. It is the most convenient way to watch series without having to worry about any kind of space, although the main disadvantage is that you will need a good internet connection.