On a draft post, you can add white space or align certain blocks of text by using the poetry block feature.
Select "More" and then "Poetry block" from the editor toolbar.
Enter the text you'd like to customize into the block that appears, and make your alignments using the space bar. When ready, select "Continue". The custom-aligned text will appear in your new post.
Note: Any text outside the block you customize will correct itself into the standard spacing once you publish the post.