PPC advertising and SEO are two very different types of marketing.
PPC is a great strategy to get your business showing at the top of the search results, or in front of in-market customers on third party websites, almost instantly.
However, it comes at a cost, and if you stop your ad spend, your ads stop showing.
SEO is a much more long term strategy that involves optimizing your website and creating new content that helps your website rank higher in the organic search results.
While the results can take longer, an effective SEO strategy will mean your website continues to rank in the search results for years to come, even after the SEO work has finished.