To change the default search form H1 on the page https://demo7.listivotheme.com/ads/ 

or any other demo like https://demo4.listivotheme.com/listings/ 

Go to Listivo Panel. Navigate to SEO. Type the new Search Results Title (H1 tag) - Default.

For more details on why it is placed in this tab and how to get the most from it (e.g., dynamically change this H1 based on your categories), visit https://support.listivotheme.com/support/solutions/articles/101000527458-how-to-optimize-search-results-page-for-seo-h1-tags-descriptions-and-meta-details