Search Engine Marketing (SEM) is closely associated with SEO; SEM can be simply defined as using paid search engine traffic to gain visibility. Paid results usually appear on the top and right of the organic search results.
The top leading player on this is Google through Google Ads and Microsoft through Microsoft Advertising.
There are different SEM techniques such as Click Through Rate (CTR), Cost Per Click (CPR), advertisement copy, and other factors, techniques, and strategies. For a successful SEM plan, you need excellent experience with keywords and other factors. Otherwise, you can waste a lot of money with an effective method and a minimum result.