You basically have two choices on how to do 2d animation. I’m not an expert here, but I’ve recently researched this myself.
- Sprite Sheets
A sprite sheet contains multiple images for each frame of animation.
Examples: sprite sheet - Google Search
This is by far the easiest to get started with, but if you have lots of customization you’d have to create a lot of images. If you were to change your mind about something, you’d have to modify all the images.
- Skeletal animation
Skeletal animation is more flexible, but takes more time to get working. Once you get it to work, you will save a lot of time though.
You could use the Unity 2D Animation package for skeletal animation. It’s quite new, so it’s a bit light on features at the moment. It could be enough for you though.
Here’s the forum: 2D Animation v2 - Preview Packages
This is the tutorial I used to get started: https://www.youtube.com/watch?v=eXIuizGzY2A
You could also use Anima2D (bought by Unity) or Spine. As far as I understand, Unity 2d animation is a version of Anima2D made from scratch to be more integrated with Unity.
There should be many tutorials for Spine, and it probably has a lot of features. I know nothing about it though.
One example tutorial for Spine (by Thomas Brush, maker of Pinstripe):
