Regardless of who builds your site, where your site is hosted or what technology is utilized in developing it, all business websites require a few basic elements to be sure your site is contributing to the success of your business and not just wasting your money.
Your domain is the "web address" and how your customers will find you on the internet.
A website is developed on a server, which is really just a specialized computer thet delivers your pages to your customers' web browser.
Functions are what your site does. Is this an e-commerce site? Are people signing up for subscriptions?
Content refers to specific text, images, audio and video files that are on the website. It does not refer to fonts background colors, or layout. Those are parts of the theme, template, or style applied to the site. "Page level SEO" refers to making sure that your text contains appropriate key words and your page titles, meta tags and descriptions are set up properly so that search engines (and your customers) can find you. It also means making sure your images are properly sized to serve quickly so that those customers don't leave when your site takes too long to load in their browser.
Without an SSL Certificate, you are putting both yourself and your customers at risk.
Without upkeep, your website will wither and die. Just having a website isn't enough. You have to make sure your site not only evolves with changes in technology, but does not become inactive and therefore ignored by search engines.