Aligning elements in a publication can help with arranging objects into different positioning, instead of elements being all in one alignment, it can typically look boring.
It can also help split certain information from other pieces of information, ensuring that the viewer is able to tell pieces of information apart. It can look bad when you have information all in the same alignment the viewer can be confused when one text is meant to be separated from another.
To change the alignment of an element, simply click the element in the editor. You will then see a white cube icon inside of a blue circle, typically to the left of the selected element. Mousing over this icon then displays the content width, align, padding, margin options along with the duplicate and remove options.