I assume you meant to ask about ad titles for ads in your campaigns, right?
What works best for ad titles varies by channel.
For search engine ads it is almost always the keyword term that most closely matches the term searched.
For display network ads page titles and/or images that are eye-catching and make people stop and say “WTF?” often work best. It does tend to vary a bit from niche to niche.
One of the nice things about all of the major PPC platforms is that you can test multiple ads and let the test results guide you to what works best. Be sure to set up a rigorous testing regime.
Keep in mind that the titles are important, but the description lines are also important. Use descriptive terms so that people understand what to expect when clicking the ads, and include a clear call-to-action.