ftp topic

Hi,
I'm a beginner with Ubuntu and I have some problems and issues.
I'm thinking to install a ftp on Ubuntu
I have a doubt about this.
Must I create all the users on the system ?
For example, if my ftp has 30 users, must I create 30 users on the Ubuntu ? or is there other possibility ?


Thanks

(I'm new in Ubuntu and learning English, Sorry for my mistakes)