Thread:Project:Support desk/What is the server directory/file that holds the HTML/CSS code for the website?/reply (7)

About the logo, you can upload your logo through the Special:Upload page (there's a convention to name the logo "Wiki.png"). Then, set in LocalSettings.php the logo URL to the uploaded file. Then, whenever you upload a new version of the logo, it will be updated without the need to change LocalSettings.php again.