There are many different tools for different tasks.
My following post is for everyone, who is questioning the same as the OP.
It's a quick overview which covers the basic programs. If someone needs more information, feel free to ask me. I'd be happy to help.
If you want to create 2d related designs:
For:
Logos, Banner, illustrations are mostly vector based images (vector = no pixel information (can be scaled endless, look it up for more details))
/Programs:
Adobe Illustrator
For:
Graphics, Sketches, Concept Art.... are mostly pixel based, opposite to the illustration part above
/Programs:
Adobe Photoshop or Affinity Pro (Almost the same as photoshop, but a one time license for a few bucks instead of a subscription)
Gimp / Linux
If you want to do animated Designs check out After effects, there are a ton of templates you can discover.
It's really great for advertisements, motion graphics..+
In a template you can change everything and fit it to your needs, also you know how to create it afterwards yourself if necessary.
If you want to create 3d related designs:
There is modeling, texturing, shading, lighting, animation, rigging, skinning, level design, environenment design, character design...+ the list goes on forever. lol
A few tools I can suggest you are: (modeling, shading, lighting, animation, rigging, skinning)
/Programs:
3Ds Max
Maya
Houdini (Top notch Industry programs for visual effects)
Blender (Open source and free, it's really great)
For creating your own textures I can suggest:
/Programs:
Substance Painter
Substance Designer
Quixel as Photoshop Plugin.
First of all, please learn the basics. You can't just start in the middle, it takes years.. This can't be done overnight.
A good starting point is to choose a simple project you would like to get done.
There are a ton of tutorials outside, you will find something.
In the end the software does not matter, it is about your skill. After a time you can jump from software to software and it becomes more easy over time to adapt to new ones.
If you are serious about this, take your time, do research and jump in.
If you find this post helpful, let me know.
I could create my own thread related to my post, + going more in depth.