WordPress is a free and open-source content management system written in PHP and paired with a MySQL or MariaDB database. Features include a plugin architecture...
If your hosting supports SFTP, use it in preference to plain FTP: it encrypts the connection, including passwords and file transfers. Plain FTP does not encrypt traffic. FTPS is another encrypted option, but it is not the same protocol as SFTP.
Check your hosting documentation for the supported protocol, server address, port and authentication method. Select the exact protocol in your file transfer application and verify the server’s identity before accepting the first connection. Upload files to the directory assigned to your website and keep a copy of anything you replace. Do not send passwords through insecure messages or grant write permissions to everyone.