Adding a logo (which is also called a Favicon) to your site is an integral part of your site’s identity. Everyone remembers the blue Facebook ‘F’ or Twitter’s ‘T.’ Firstly, your desired logo should be a file that is 36 pixels by 36 pixels, or 16×16. Just a really small square. Then, this image must be converted to a ‘.ico’ filetype. There are many converters online that do this, a quick google search will be fruitful.

The red boxes show where your Favicon gets displayed. The green box is what will appear if you have not yet uploaded one.
My go-to for executing this task is to use Genesis, from the side menu in your dashboard: hover over ‘Genesis,’ then click ‘Upload Favicon.’
Once on this page, click ‘choose file,’ find it on your computer, then click the ‘Upload Favicon’ button. That’s it!
Alternatively, from your dashboard, you could click ‘Appearance’ then ‘Customize’ then ‘Site Identity.’ Here, you can upload a square photo that will act as your logo. A bonus of doing it this way is that it does not need to be so small, nor does it need to be a ‘.ico’ filetype.
Additional video:
Another alternative way to do it:
Thanks to WP Beginner for the video!