As search engine algorithms continue to progress, some SEO (search engine optimization) practices have shifted in their importance as a ranking factor especially with Google search. Practices that were once important ranking factors have lost some of their influence on search engine ranking within the modern-day SEO landscape. In fact some previous practices can work against your ranking. Additionally, as more and more new ranking factors are introduced, the impact of any one factor is reduced. The H1 tag has long been an example of an influential and simple ranking factor and an important signal to search engines as to what a page of content is about. The proportion of the H1’s influence on rankings compared to the overall picture has reduced over time, but is still measured as an very important ranking factor.
The header tag, <h1> tag in HTML, is usually be the title of a post, or other emphasized text on the page. It will usually be the largest text that stands out such as a title similar to what you find in printed documents.
With a simple step you can add h1 tags to your Weebly website.
Unfortunately currently Weebly drag and drop Title element is not h1 specific but you can add a h1 tag to you Weebly website
h1 Code Example:
<h1 style="color:#0d97d4;">Your Title</h1>
For further information on h1 tag visit http://www.w3schools.com/html/html_css.asp
Note: Use the Weebly Embed Code by simply dragging and dropping the Embed code to where you would want the and paste code within the Embed Code Element.