Choosing program

I agree with JonathanArias​ that it depends on what kind of illustrations and drawings you'd like to create.

Many digital artists sketch on paper first, and then scan their work for further inking and colouring. To do this, there are two basic approaches (which can be combined, btw):

1. After scanning a drawing, it is cleaned up, and the artist then uses a graphic tablet (such as a Wacom tablet) with a pen to draw and paint digitally, add lighting, and so on. The advantage is that this workflow is very close to what you would do with painting and inking for "real". This is what is called "digital painting/drawing".
2. After scanning a drawing, the artist uses a vector tool to draw vector lines, and fills areas with colours. This is rather different to (1) where the image is comprised of pixels only. The advantage of vectors is that they result in very sharp and controllable lines and areas, although it feels much less like drawing. Lines can be easily edited to get it exactly right.

Some drawing applications can do both, giving you the best of both worlds.

Whichever software you choose, at some point you will want to invest into a Wacom tablet or a similar product, because drawing with a mouse or trackpad isn't a lot of fun nor fast or precise. It is too indirect. A good pen and tablet are just about essential to have as a digital artist. I have a Wacom Pro Large, but that one is quite expensive; a smaller one will suffice as a beginner.

For (1) an bitmap digital paint app works best. For (2) a vector illustration application works generally best.

If you are interested in digital painting and colouring (1), save yourself a lot of money, and download Krita first to start out with. Krita is an extremely capable digital drawing and painting app, and completely free. Arguably a much more pleasant experience to paint and draw with than Photoshop, because it is focused on that job. By saving the rent for Photoshop, you will be able to purchase a Wacom tablet instead, which is FAR more important than the choice of digital drawing and painting software.

Krita | Digital Painting. Creative Freedom.

Many tutorials online for Krita.

Some applications combine (1) and (2): for example, ClipStudio Paint, which is again geared specifically towards this type of work, rather than Illustrator. ClipStudio is an excellent choice for vector inking purposes, for example. It is an industry standard for comic artists nowadays. Illustrator does a proper job as well, though. Just not as focused again as ClipStudio in this regard. But in any case a graphic tablet is more or less required for good and efficient inking.

Having said that, if you want to create the type of controlled sharp-edged illustrative art and need full control over vectors, an app like Illustrator is almost a must. There are free alternatives such as InkScape, which you might want to look into to save some money when starting out. It will also convert your sketches to line art, which can then be adjusted. For this type of work you might possibly get by without a pen and tablet, just using the mouse. But it is rather 'not fun', and a more technical process.

The Adobe applications are a great option too. But if I was in your shoes starting out, I'd invest in a good drawing tablet first, because the software is less important at this stage. (Besides, for digital painting the free alternatives are at least as good as Photoshop). Of course, if you are planning to work in the industry, Photoshop and Illustrator experience are often a must have, although no-one will care which software you created your art with if it is of high enough quality. Working for a company you may have to be able to use them, though.

To really decide what works best for you, please share more information with us about what kind of art you are interested in creating.

If you are scanning artwork you will find dust and scratches in the artwork. and photoshop will quickly help you clean up those scans. Plus you may find other imperfection you may want to clean up, and you might start using the clone tool, and retouch on and on ...

Anyways. If you are going to scan at a high resolution and will clean up after, that is photoshop work.

Drawing. again, you can draw from photoshop.  or you may use a free app in the ipad for drawing and load your drawing from the ipad to photoshop. is that the kind of workflow you think you would like?or will you want to draw from the computer?

take a look at this:

How to Draw: Adobe Photoshop Sketch with iPad Pro & Apple Pencil  | Adobe Creative Cloud - YouTube

To learn how to work with photoshop, sketch i will only recommend one thing. Lynda.com

and this is the course i would say to start with:

Photoshop CC 2019 Essential Training: The Basics

So, all in, you will be at about $20/month for photoshop, I think $30 a month for lynda.com. Not bad to start, see how you like the workflows, experiment, thats important.... see what first for your budget and your personal needs. You may want an apple pencil, i got mine from "LETGO" for $50 used. works fine.

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The same can be accomplished from illustrator..... pay $20/month for single app. live trace, rework/color your drawings, export to whatever format you want at the end. done.

Last, what kind of drawing are you doing? sketching, line drawings? if so yes, illustrator might be of your liking with the live trace option.... turn it all to vector lines, and color it... you will be working all vector so you can print things the size of a football field and you will have nice clean sharp edges....

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Can you show us what kind of drawings are we talking about? what do you want to do with the drawings?

Hi Line:

It sounds like your primary focus is drawing, so I second Steve's recommendation. Start with Illustrator, and then see where life takes you.

~Barb

I'd focus on Adobe Illustrator first. It's best designed to convert drawings of different kinds into vector art that can be further edited digitally,

InDesign could then be used to PLACE your Illustrator drawing into a publication with other text and graphics. Photoshop primarily focuses on images themselves, including creating composite image files with many layers.