Go to the html file and search for the navbar-brand.

                                    
            <a class="navbar-brand" href="index.html">
                <!-- Logo icon -->
                <b class="logo-icon">
                    <!--You can put here icon as well // <i class="wi wi-sunset"></i> //-->
                    <!-- Dark Logo icon -->
                    <img src="../../assets/images/logo-icon.png" alt="homepage" class="dark-logo" /> <!-- Put Dark color Logo Icon -->
                    <!-- Light Logo icon -->
                    <img src="../../assets/images/logo-light-icon.png" alt="homepage" class="light-logo" /> <!-- Put Light color Logo Icon -->
                />
                </b>
                <!--End Logo icon -->
                <!-- Logo text -->
                <span class="logo-text">
                    <!-- dark Logo text -->
                    <img src="../../assets/images/logo-text.png" alt="homepage" class="dark-logo" /> <!-- Dark Logo icon Text Here -->
                    <!-- Light Logo text -->
                    <img src="../../assets/images/logo-light-text.png" class="light-logo" alt="homepage" /> <!-- Light Logo icon Text Here -->
                    />
                </span>
            </a>
                                    
                                

Put the image in assets -> images Folder.