Pay per click advertising is the form of marketing where the best advertisers like Dux Digital run their ads on the top right-hand side of the screen, and they will be charged only when a user goes to their ad and clicks the advertisement. The amount of money the advertiser has to pay when the user clicks on the ad depends on the keyword that the user searches.
Search engine marketing is when the advertisers will be able to post links on top of the search results. If a user enters a particular keyword on the search engine, they will be able to see your ads along with the other search results. SEM is more of a paid advertisement, and the advertiser has to pay for the link irrelevant of the user clicking on the ad.