Brand personality is a set of human characteristics that are attributed to a brand name. – Investopedia
You meet certain people in life who ignite positive vibes in you, and you rarely forget them for a very long time.
Sitso was one of such people I met in Junior high. She oozed so much cheerfulness and optimism. Being unhappy around her was utterly impossible.
That was her personality.
A brand needs a personality as humans do. This helps customers to clearly identify you from the bunch.
Create how you want customers to perceive your brand and the image you want them to project when they associate with you.
Pick that one word that best describes you. Example; Playful. Expand that word a little bit to include other sub-words to give your brand some dynamism.
Again, Playful could include colourful, vibrant, happy, humorous, experimental and so on. A thesaurus could be helpful here.
Finally, the colours, images and typography on your website, social media platforms and publications should bear the brand personality.