How not to screw up with optimization?

Question

Joomla

Good afternoon!
What are the main points to be observed in order for the search engines to index.
I understand a little about this topic, but what of all the variety is it really necessary to use?
As for me, this is: keywords, description, robots.txt, site.map
But again, I can be wrong because the developer, but there is no SEO experience.
For example, now there is a question, is it necessary to semantically highlight phone numbers, email in a public offer agreement?

Answer 1

robots.txt, sitemap
No, it doesn `t need

Answer 2

The main thing is that the texts are of high quality and unique. The rest is hundreds of times less important.