Your interviewer may ask this question to find out what experience you have with helping to build on a brand's appearance in a way that will appeal to their buyer persona. You can answer by describing design conception and testing for various forms of content, such as logos, etc.
It's not necessary to discuss actual design steps or tools to answer, but you do want to consider understanding the customer's identity goals and their audience as part of the planning and execution process.
"I recently worked with a client that wanted to revive their brand's visual appeal. I developed a good feel for the brand through many conversations, interactions with the product, and even their audience. As an account manager, my job was to help translate that feeling into words. I liaised between the client and the graphic design team to create a logo, color scheme and overall concept for the website, social media accounts, and collateral. Everything had to be consistent - our goal was for the audience to recognize instantly, even subconsciously when they came into contact with the brand's materials. I helped the client to involve other departments of their organization and their audience through testing and polls. The engagement and backing of the many people associated with the brand made this facelift a success, and once final changes were rolled out, they were embraced by most."
"I am often tasked with coordinating visual branding projects in my current position. To make these projects successful, I ensure that all materials and communications related to the project are delivered to the right parties and stored properly for future reference. While handling the project's administrative tasks, I'm essentially a second set of eyes to the designers and project managers. I speak up if I see something missing or not quite right, I help with reporting on information that's needed, scheduling conferences, ensuring we meet deadlines, and other details that may otherwise be overlooked."