How is logos used in everyday life?

Logos can be used to tell something apart form another. Example: McDonald's has the "M" Logo, if you saw a McDonald's with a Purple Bell, it would signify Taco Bell. So it shows the ownership of one company and how to tell the companies apart.

LIKE THOSE KIND OF LOGOS OR THE OTHER KIND?

Logos are used everyday in stuff like commercials to persuade viewers to buy their products with logic; Saying something like this Product is the best product based on consumer reports and uses. But they are also used in situations where there is a need for a audience to be persuaded such as a court room a lawyer would want to persuade the jury to vote guilty, or not guilty by presenting facts and evidence. Or if you want someone to vote for you in student council you would provide reasons why you would be qualified for the role.