While we create a new account in cPanel, you may find following default files and folders:
public_html: To make your website publicly available over the Internet, please upload your web pages and images into this folder.
public_html/cgi-bin: CGI Bin directory.
public_html/images: It is used to store the images for any webpages you upload.
public_ftp: It contains files to be accessible via anonymous FTP.
public_ftp/incoming Files: Files uploaded via anonymous FTP.
.cpaddons: Stores information about cPanel Add-ons for particular account.
.trash: Items deleted or moved to trash in cPanel File Manager.
public_html/.htaccess: The main .htaccess file for the pages served on this cPanel account over HTTP.
mail/: It stores the mail data.
mail/new: Stores incoming mail that has not yet been marked as received by IMAP.
mail/cur: Mail sitting on the server.
mail/tmp: Temporary directory for mail.
tmp/: Temporary files created by cPanel in various activities. Third party scripts may also use this directory for their own temporary files.
tmp/analog: Temporary files for generation of Analog stats for your website.
tmp/awstats: Temporary and configuration files for generation of AWStats for your website.
tmp/awstats/awstats.yourdomain.com.conf: Configuration file for generation of AWStats for a website.
tmp/cpbandwidth: Temporary directory for tracking bandwidth usage through cPanel.
tmp/cpbandwidth/yourdomain.com-bytes_log: Number of bytes tranferred by yourdomain.com.
tmp/webalizer: Temporary files for generation of Webalizer HTTP stats for your website.
etc: Stores other information related to your website.
Mostly .(dot) files are configuration files for the respective service. e.g., .softaculous, .fantasticodata.