Branding guidelines are a set of custom typography specifications that portray your brand image. Your brand image should use the same type faces in all marketing collateral that leaves your office. By using the same imagery and fonts, it trains your customer what to look for when they see your brand. Using consistent branding conveys a professional look that makes you look serious about your work.
If you're a franchise, it is a proved successful standard to provide to your stores.
If you already have a logo, that's great!
Rae Design can create branding guidelines for you!
Here are some links to great examples of branding guidelines: