By default WordPress shows the site title in the Header area, you can change the font style from WordPress Customzier => Design => Logo Font Family or you can easily upload logo in JPEG or PNG formats.
Got to WordPress Customizer => Site Identity where we have site icon field and 3 logo fields.
- Site Icon: Upload here image with 512 x 512 dimensions which will be set as Favicon
- Logo: Upload Logo and set you Logo width and height
- Logo HDPI: Upload logo for Retina displays which should be 2x big then logo uploaded in Logo
- Small Logo: Logo uploaded here will be visible in More Button Menu
Besides these options you can set here:
- Footer Text (copyright text)
- 404 Page image
For adding Logo for Mobile devices please read Mobile section of this documentation.