Personally I prefer to start on an ipad, as it is way easier than a drawing pad on a computer, you'll also want to get an apple pencil with that. Some people prefer to use their fingers to make art but I find it way easier to deal with smooth weighted line art if you use an apple pencil.
There are many different programs for art that have many different uses, depending on what kind of art you want to make programs will vary with importance. I recommend starting with Procreate as it was the first art program I could figure out. Procreate is a mobile program that is $13 USD, while yes it costs money, it is very useful and it's still the main program I use for every artwork.
When it comes to digital art, size does matter. When you make an artwork on Procreate you might wonder things like "Why is my artwork pixelated" or "Why can't I use more than a couple layers" well these all tie into the size of your canvas, Procreate limits the amount of layers you can use depending on the size, but thats not what we're concerned about. You want your art to be the right size, personally I always have my canvas (widthxheight) and then I save my artwork as a png.
I dont do much traditional art anymore but I do still have lots of advice to tell. Starting off with Pencils. Now of course for traditional art you can use any pencil, it's not about the pencil it's about the artist. But here is the brand I recommend: Faber Castell, these are some high quality pencils, which I recommend getting all kinds of different pencils. There is 2B, B, HB, F, and H. Faber does have more such as 6B or even 8B. For example HB is your average pencil for school. For mechanical pencils you should have different sizes from smallest to largest: 0.3 0.5 0.7 0.9 1.18 1.4 2
Like pencils, inking pens have different sizes, which I recommend getting all the sizes you can. Brands I recommend for Inking pens are: Pigma Micron, Faber Castell. But if you're looking for something REALLY good, I recommend getting a fountain pen, while more expensive they are very high quality and will give you good line weight and smoothness. Although I cannot recommend a specific brand as I don't have a fountain pen myself
As for paper, just use any paper you have, if you want to paint then use watercolor paper, other than that just use normal paper if you're using dry art supplies.