No, section titles do not have to end in a period. But a common convention in the U.S. is that when section titles are used, they appear in bold and are followed by an unbolded period. For example:
- Development Credit. The Client shall acknowledge the Developer as the Website developer on the Website page entitled ...
The convention promotes clarity and helps courts that later have to interpret the document to better understand the parties' intent.
For a written contract, an alternative would be to place the title on its own line with the text below. Some contracts omit section titles entirely. Others add them but with an additional section explaining that the titles are not to be used to interpret section text groupings.
Online resources like Law Insider and Onecle have large databases of sample contracts that should help with both formatting and content. If you'd like to learn contract drafting and revising somewhat more formally, then a good text reference is Tina L. Stark, Drafting Contracts: How and Why Lawyers Do What They Do (Wolters Kluwer 2d ed 2014). (The above snippet is from Stark.)
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