A coat of arms is a visual, symbolic design historically used to identify individuals, families, institutions, or organizations, particularly in European heraldic tradition. It is closely associated with heraldry, the study and design of armorial bearings, which emerged in the Middle Ages.
It's important to note that not every surname has an associated coat of arms, and the use of a coat of arms is more common among European nobility and aristocracy. Additionally, the concept of a coat of arms is often tied to specific individuals rather than the surname as a whole.
There are many different coat of arms associated with individuals for the surname LeBlanc. The design would have been granted or adopted by a specific individual or family at some point in history. Without specific details about which LeBlanc family or individual is being referred to, it's challenging to describe a precise coat of arms.
A google search of the LeBlanc coat of arms will reveal many different and confusing variations of shield, supporters, devices and colours; most typically found on web sites that make a profit from selling attractive framed images of a coat of arms or crest device with perhaps a vague history of the surname. Some of the information may very well be legitimate while others appear to develop a "history for profit" and sell it whether it is real or not. This web page started out as an information source but ended up being a commercial for these web sites that "create" a coat of arms for the masses. Sorry about that but these things are very popular and affordable, and they constitute all there is these days for coat of arms information.
For the LeBlanc chapter, there appear to be two distinct designs that emerge from the melee.The more predominate is a shield with some type of bird, a chevron and three devices. The other less common design is a lion on a shield. As for colours, blue and gold appear to be a consistent theme.
In Canada, there exists a "Canadian Heraldic Authority", where if you are deemed acceptable byway of volunteering and community involvement, and you can afford the exorbitant fees, you could have your own official Coat of arms, flag or crest created for you. According to this Heraldic Authority there is no concept of a family coat of arms, being issued only to individuals and their descendants.