Margin in spacing add-on

Not too sure what you mean? Can you explain a bit more?

Spacing Add-on have padding size, but have not margin size, for example the distance betwen two DIVS in HTML.

The Separating space determines the margin between elements: https://docs.generatepress.com/article/separating-space/

Which specific elements are you trying to add spacing between?

Sorry, do not explain me well, for example, if I want to separate the menu from a section. The menu has no margin, the sections also have no margin.

To add margin between sections, give your section a custom class, like “section-margin”. Then, add this CSS:

.section-margin {
      margin-bottom: 20px;
}

For the navigation, try this:

#site-navigation {
    margin-bottom: 20px;
}

Yes Tom i lnow how use CSS, but i ask you if is possible include this caracteristic in the ADD-ON in a short time?

For Sections, most likely not. I think you're the second person (out of many) to ask for it. So CSS is probably the best bet here.

The main navigation could probably use this option - it's something I'll look at adding :)