I was unaware of the difference between these two for a very long time. When I read, it just slipped by my attention whether which one the author had chosen to use. However the detail is minor, it still is important to know the difference and make the choice for yourself in your writing.
The most common form used in every day writing and speech. Some authors fall into the habit of using ‘He said’ in their dialogue such as,
“I have never seen such terrible manners.” He said.
Of course there isn’t anything wrong with this way, for example if your story is in first person, ‘He said’ is perfectly acceptable as past tense when not referring to your other characters. But if your novel is in present or future 3rd tense, ‘said he’ is the more professional option. For example when using a name for your character there is a major difference in the flow of your sentences.
Present 3rd person: “I will always love you” Lucy said. Vs “I will always love you.” Said Lucy.
(This rule doesn’t apply to 1st person at all)
Past 3rd person: “Don’t cry, please I won’t be able to bare it.” Stephanie said. Vs “Don’t cry, please I won’t be able to bare it.” Said Stephanie.
Most novelists use ‘said he’ as it is a slight but sophisticated difference. Using ‘said he’ is the difference between everyday writing and editor approved writing. It changes the flow of your sentence structure so deciding to use it in your dialogue is an important decision.