A logo in any website especially for a company tells us what the company is about. It gives us an Idea of what are the values of the company.
Even though the size of the logo is very small compared to the other elements in a page it contains a lot of Information.
SharePoint just like any other website requires a logo to represent the company. And not anyone can change the logo of the website, it can only be changed by the Site owners.
In order to Insert or change the logo of the website, one would have to click on the Gear menu at the top right hand corner and click on Site Settings. Under the section Look and Feel, click on Manage logo. And you have two options to either Import your logo from your computer or SharePoint. Once you select your source, you should be able to notice the new logo on your SharePoint website.☺