When registering a trademark for your logo, the decision on which colour version to submit will also depend on the jurisdiction.
In most countries, we usually recommend that clients register the version of the logo they use the most in connection with their goods or services.
However, in some countries, including the US, Canada, Australia and New Zealand, it is generally recommended to submit the logo in black and white. This version will then protect all colour variations.
It's also worth mentioning that in some countries, such as the UK, it is also possible to file a series mark. A series includes multiple marks that may have only minor differences. If you file a trademark application for a series, you can include multiple colour variations of your logo. They will all be officially protected and included in the trademark certificate.