SEO (Search Engine Optimization) is the process of updating and optimizing your site's existing data with keywords, schema keyword phrases, metadata optimization, image/video tagging, etc, basically filling every single blank box and then some to make sure Google recognizes your site as a serious competitor in your area and begin ranking it. Once ranked, you will begin to drive FREE traffic that's looking for what you're selling! SEO is a long-term investment.
Advertising is akin to a short-term strategy, it uses Google and social media platforms to search for people in your chosen area and attempt to divert them to you at a specific fee per customer usually whether they buy or not!
A combination of both is always best but SEO by itself is extremely labor-intensive, that's why a team like ours is hired, to save you mental space and let your focus on one less thing!