SEO stands for search engine optimisation.
`SEO is the optimisation of your website or webpage to help you gain rankings on a search engine such as Google.
Keywords are words or phrases used to find what content you would like on a search engine.
SEO can be time consuming in a competitive industry or really easy in another industry. The complexity can be both simple and difficult depending on your goals.
Yes in short it can effect your ranking and also an SSL certificate can.
We would say if you take you business seriously yes. Having an SEO strategy can get you to the top in your industry or keep you there if you already at the top.
There are many online tools now a day that help you find the right keywords for your business. Also think like your customers would. What would you type into google to find what you wanted.
Absolutely the more content you have on your website the better. If google sees that you are a good source of information then it will promote you higher.