Form fields have something called a tab index. So when you press the tab key it will know where to go next. However when a page has multiple forms the indexes can get mixed up, unless they are clearly specified in each field.
Some wp form plugins give you the ability to add the form index range, that way if there are multiple form elements in one page they won’t overlap.
So to answer your question… the tab order will change from page to page depending on the form elements in it.
Here‘s some more reading on tab index.