You can set the alignment of paragraphs and headings so that they align on the left, right, or center. Left alignment is the Dreamweaver default. Setting the alignment on the right shifts the text flush to the right margin of the web page. Setting the alignment to the Center, centers the text equal distance from the right and left margins of the web page or table cell containing the text. See also Adding Paragraphs and Headings
You can also set the alignment to Justify. Justify is alignment is centered with both left and right margins aligned. To get these straight edges on both sides of the paragraph, Dreamweave adds blank spaces where necessary to achieve the justified alignment so that the line ends flush with the right margin.
When you press Enter to insert a new paragraph, Dreamweaver applies the same formatting as the previous paragraph. So if your first paragraph was justified and you hit the enter key to insert a new paragraph, it too will be justified.
The checkmark in the Alignment menu indicates what type of alignment is applied to the selected paragraph. Notice that the procedure for aligning the paragraph text above is the same as it is for aligning the Heading below. The Heading below is Center aligned while the Paragraph text above is Left aligned.
See these related Dreamweaver Tutorials:
Creating a Web Site
Using HTML Tables
Web Site Management
Cascading Style Sheets