Branding is great way to improve the visual look and feel during the login experience but may also help mitigate phishing compromises in a small way by providing uniqueness. It only takes a few moments to brand your tenant and branding will also start showing up in a number of different areas when you use Microsoft 365 services.
This video takes you through that process and shows you how easy it is to set up. a link to the video is here:
and the article mentioned in the video is here: