Make your mark!
Once you've made your edit, look for the blue "Publish changes" button in VisualEditor, or the gray "Publish changes" button in WikiCode.
For both, you'll want to edit what's called an "Edit summary." Describe what you just did, so other editors can make sense of your edits. For example, if you added a citation, you would write "added citation," followed by why. For smaller edits you copyedited or fixed a grammatical mistake, you could write "c/e" for copyedit. There's no real "official shorthand," just make sure you convey the intent of the action you took when you edited the page.
In VisualEditor, you'll be asked for your edit summary after you save your edit. In WikiCode, you'll want to type your edit before you save.