To upload your logo, go to Customizer -> Site Identity. You are free to use default text logo version or upload a custom logotype image.
Scroll down the panel and you will see some more options where you can limit logo maximum height for different resolutions. This may be useful if you have really large logo on desktops but you want to make it smaller on mobile devices where there is less room for big elements.
That’s possible to combine both text & graphic logo parts. But you can disable text part by unchecking Display Site Title and Tagline if you don’t need it.