In that way, when you are developing some code, you store it in a function and just below hooks this function with add_action and just after you call do_action.

A better description for do_action is that it calls all functions that are hooked to it, as if it was a list of functions calls. Doing as I said, your function will be called as if you had called it there.

But the difference of calling a function and using an action hook, aside from the action allowing to call a bunch of functions at once and letting other ppl to call their functions inside your code, is that other ppl can use the remove_action function to remove your original function from being called. And after it, they can develop their own function and add it there, replacing your original function from their, which may be better than yours or just do something differently that fits better their needs.

That’s a tremendous powerful feature!!!

And since you are teaching ppl how to do it, I think it is also important to teach them the importance of using prefixes on our functions (and hooks too!), so that they don’t conflict with others’.

TY again !!