filezilla

Hi,

it's the first time that I use a paid webhosting account generally I used a free account so I uploaded my files directly to the server so I want to know why here we are using filezilla to upload files? and I want to know what does the logon type mean I choosed the normal but what does it mean, plus what does the transfer mode mean and finally what does the encryption use plain ftp mean does it mean that my data is not sent encrypted is it sent as visible if so how can I make it encrypted?

thank you.