I've been drawing digitally for over 15 years, and I started out with some very limited tools. You're definitely in a better position these days to pick up digital drawing tools for a reasonable price which will help you have a far easier time than I did back then!
Tools
While a lot of artists will insist "it's not the tools which matter, it's the skill behind them," I respectfully disagree. Good tools help enormously. They still require skill to use well, but those skills are far easier to learn when you're not being actively hampered by the tools you're using. (I'm a teacher, so I speak from experience here.)
I use an iPad Pro, with an Apple Pencil and an app called Procreate. Procreate is one of the best beginner-friendly drawing apps out there, and I highly recommend it. It's only on iPad, but iPads themselves are also fantastic to draw on. They feel very natural, more like drawing on paper than any other digital art experience I've had. You're also drawing directly onto the screen, which removes the learning curve of using a separate drawing tablet.
The newer iPad mini's are Apple Pencil compatible, and much cheaper than the Pro's, so that could be a good one to look at as a beginner.
If iPads aren't your thing, I'd recommend using a regular computer/laptop, buying a drawing tablet, and using a program called Clip Studio Paint. (It's available on PC, Mac and iPad.) Clip Studio is the industry standard drawing program for webcomics. It's more confusing to learn than Procreate, but it's also got a lot more features. As for drawing tablets, Wacom Intuos are great, but they don't have a screen. Screen tablets designed for PC/Mac are expensive, but may be worthwhile long-term because they're easier to use. I only have experience with Wacom, but other artists here may be able to recommend some of the cheaper brands as well.
Techniques
It's nearly impossible to give a quick overview, because there are so many digital techniques! Most stem from traditional art theory though. So watching YouTube videos on colour theory, composition and so-on will be very helpful. Also, if you find an artist you really like, seeing if they have speedpainting videos available can give you some insight into the steps they take to create their work.