The difference between SEO vs SEM Definitions

What these concepts mean SEO and SEM?

SEO "Search Engine Optimization"

This concept is linked to the mechanism of applying techniques on the pages of a particular website to achieve their appearance in the search engines, and the purpose of this work the emergence of the pages of that site in the forefront of search results and the first page is always the goal of all entrepreneurs on the Internet.

The concept of SEO is related to implementing strategies that do not need any budget.
For example, for example, the size of articles written on websites should not be less than 300 words in the worst case and preferably up to 700 words or more. For example, the meta tag of the site and its pages should be well thought out, and of course creating permanent links to be engine friendly is one of the most important examples.
All these examples are just a simple thing in SEO.

SEM "Search Engine Marketing"

In this concept we are talking about marketing that is done by search engines, in which case we need money to market!

One of the most important systems or sites that provide this service is Google AdWords, so that website owners and anyone who wants to use the search engine can market it so that the ads are displayed on the search results page. 

Search engine marketing is very broad and needs expertise based on many experiences. In every company, there is a person who specializes in advertising, in the field of search engine marketing in particular, or is responsible for PPC ads.
As for the importance of this field in e-projects and others, it has become a fundamental thing in every major or emerging company, and on remuneration