Changing the padding or margin of an element is very easy using the Advanced Options. To do that, just click the specific element (i.e. Headline), then go to the cog gear icon and click Advanced Options.
On the left hand side of the screen, go to the Positioning tab to access the padding and margin settings.
To individually set the padding or margin, you can directly type the number of padding or margin you want to set (the inner box is for padding and the outer box is for the margin). Or just drag just hover the line and drag it up or down / left or right.
You can also set the padding or margin as a whole. To do that, click the link icon and drag the line for padding or margin.