How to be able to use icons inside posts

I am new with Ghost and I’d like to add icon inside the core text of my post. I would like to have approximately 10 different icons that I could use in any posts. Those icons should be linkable and also stored within the environment. I found lot of examples for social media icon to add in the footer notes but nothing about simple icons.I believe is with code injection but i dont know what to put and where to store the icons and how to use them within the text! I would like also to have recommendation on websites with icon library free of use.

Thanks for your help