Regardless from which way you look at it, Keurig machines are the most user-friendly coffee machine out there. They are well known for being convenient because they do not require grinding or measuring grounds, matching the perfect coffee to water ration, and other processes. Internally, they work a lot like drip coffee machines: they heat the water up, let it sit in the grounds mixture, and then have the filter separate the liquid which then goes directly into your mug.
To use a Keurig machine you only need to fill the water compartment, and place your K-cup in the appropriate slot and press a button. K-cups are convenient because, apart from being available in hundreds of different flavors including non-caffeinated drinks like hot chocos and teas, the grounds and filters are already sealed together. Because everything is contained in the pre-made cup, there isn’t a lot of deep cleaning to be done either: you just have to wipe the exterior clean occasionally. The inside parts can be wiped clean once every week or two, particularly the cup loading slot and the beaked part which pours the beverage in your mug. Some newer machines even have an automatic cleaning function which flushes the whole system with hot water to rinse the dirt away.
If you feel the need to refrain from using the K-cups, maybe for their higher price or because you can’t find the right flavor, you can always purchase a separate filter which enables you to use your own grounds of choice. To do this, simply place the filter in the slot and then pour your coffee on top of it, like you would with any drip coffee machine; close the lid, press the button, and enjoy you coffee. This requires a bit more cleaning, especially if you put too much grounds and it overflows) and disposing of the filter (if the paper ones are used) though.