I have a doubt with one request/response across Web Browser and Server with SSL Certificate. Please, imagine the following case (similar question here):
I want that the server, response a HTML to the user (in his/her browser) with access to one file in the FTP, for example:
<a href="ftp://theftpserver.com/files/acounts.pdf">Download file</a>
<a href="ftp://username:firstname.lastname@example.org/files/acounts.pdf">Download file</a>
Yes, SSL will make it more secure because your communication with the server will be encrypted. It is even better if you have a web server (an API endpoint for instance) receiving the requests from your frontend, contacting the FTP server, getting the file, and responding back with it. This way, the frontend does not need to know about the FTP server. Another good idea is to hash the password and before sending it.