For FTP over TLS (FTPS), from the cPanel & WHM 11.38 Documentation:
To configure your ProFTP server:
Next to TLS Encryption Support, select whether you wish for TLS encryption for FTP connections to be Optional or Required.
To configure your Pure-FTP server:
Next to TLS Encryption Support, select 1 of the following options:
Disabled — Disables TLS encryption.
Optional — Allows your users to
specify whether they wish to use TLS encryption.
Required (Command) — Requires TLS encryption on all commands being issued to the FTP
server. This will help to protect login and password information.
Required (Command/Data) — Requires TLS encryption on both commands
being issued to the FTP server and data coming to and from the FTP
server. This will protect both passwords and files being exchanged
between client and server.
Select "Required" for ProFTP, or "Required (Command)" at minimum for Pure-FTP, depending which FTP server you have installed.
This should be located here:
Home >> Service Configuration >> FTP Server Configuration
FTP clients will then need to be configured to connect over "TLS/SSL".
Note: if this is not available based on your account permissions, then you'll have to upgrade to an account that does have this permission, a VPS, or a dedicated server.