You may not realise that you can customise the top navigation bar in Office 365 as a global administrator. This will give you some branding and navigation options across your tenant.
Navigate to Organizational profile in the Admin center and select to Edit the option Manage custom themes for your organization.
You now need to simply upload the required graphics but you will note that you can include a URL for the logo you add. This URL can basically be any web site address.
From the above, you can see that I’ve uploaded a logo, set the logo link to point to the default SharePoint site for the tenant and set a background image for the banner.
If you scroll further down the page you will a number of additional options, including the ability to display the full name for the logged in user, which I have selected.
Save you selections.
Without the banner background your navigation will appear like what you see above.
With the banner background your navigation will appear like what you see above.
If you then click on the logo you’ll be taken to the web site you entered during the configuration. In this case, to the default SharePoint site for the tenant.
Hopefully, you can now see a few more branding options for your Office 365, including the ability to link to any web location via a logo. That, I find is a very common request from many organisations.