I sometimes use svg's define symbol method `<defs>` (https://developer.mozilla.org/en-US/docs/Web/SVG/Element/def...), you combine all the icons you use into one document that you load with display none and then reference those symbols anywhere else on the page using svg `<use>`.
Use graphics for icons.
For a11y reasons, include a text alternative, like the alt attribute on <img> elements or adding a <title> in your <svg>.