The General Fonts & Colors element is used to update the fonts and colors for the basic elements of your email signature. For example, you can update the field and background colors, then the type/color to be used for your contact information:
You will be able to then make your email signature conform to your organization's corporate branding.
Every template in Signatures for Office 365 is different and the available options will vary. If you aren't sure how a change will affect your email signature, you can simply try in and check the signature preview. If you don't like how it looks, simply cancel the change.
The example below gives you an idea how these settings work by showing how fonts and colors affect one particular template:
General fonts and colors settings have been updated...
These changes affect the signature as follows...
If you change fonts and colors, but find that there are still parts of the email signature that haven't been updated, you will need to check options within other signature elements to find the appropriate setting.
In the above example, notice that the social media icons are green - this color is determined by settings in the social media strip element.
Your logo palette
When you add a new logo for an email signature, the dominant colors in that logo are detected and automatically assembled into a color palette, ready to use. You will see this palette when you choose to change any color settings either here or within any other elements where a color setting is available:
This is a really quick, accurate way to apply your organization's color scheme to the various elements of your email signature.