These guidelines provide you with guidance for using the Kubernetes logo. All artwork is made available under the Linux Foundation trademark usage guidelines. This text from those guidelines, and the correct and incorrect usage examples, are particularly helpful:
Certain marks of The Linux Foundation have been created to enable you to communicate compatibility or interoperability of software or products. In addition to the requirement that any use of a mark to make an assertion of compatibility must, of course, be accurate, the use of these marks must avoid confusion regarding The Linux Foundation’s association with the product. The use of the mark cannot imply that The Linux Foundation or its projects are sponsoring or endorsing the product.
Additionally, permission is granted to modify the Kubernetes mark for non-commercial uses such as t-shirts and stickers.
The Kubernetes logo is available in 2 formats (PNG & SVG), 3 layouts -- horizontal (also known as landscape format), stacked (which is closer to square), and icon (which does not include the name and is square), and 5 colors (color/black/white/all-blue/white-text) -- so over 20 versions -- in the CNCF artwork repo.