Let’s make a long story short. I will also keep it simple.
The google snippet is very important. If somebody is searching for something, the search results are snippets. Each snippet has a title and description. It means, when I develop a website and am doing a SEO (search engine optimisation), you have to provide for a google snippet:
The maximum title length is 55 characters including spaces.
The title is the most visible part, in bold font. Use important keywords. Think of marketing. Try to get the attention of your audience.
The maximum length title is 160 characters including spaces.
Provided you get the visitor’s attention, in the description will be visible what the website is about, why the visitor should click and visit your website, and what the visitor can expect. And again, use important keywords in the description.
Title and description for each site
Ideally each page of your website should have its own title and description. These are the basics.