Post title or H1 post title is the title your website visitors see at the top of every WordPress post. It is surrounded by < h1 > HTML tags. It means that this is the most important heading in the whole post. This post title also attracts your website visitors attention, so they will click it to open the post and read it.
The SEO title is the one used by search engines when they index your website. It is also known as the meta title and is important for website ranking and appearance in search results. Search engines pay attention not only to < h1 > tags, but also to < title > tags. The SEO title isn’t visible to regular website visitors, but it’s used in browser tab.