Can I transfer my music from my iPhone to my iTunes? If so, how?

Hi, I have a new computer and i forgot to transfer my files. My itunes library is completely empty but i have all my songs in my iPhone. Is there a way for me to transfer/save/copy the music to my computer/itunes? If so, how do i?

Also, a bonus/extra question: Whenever i download files such as mp3 files to my account, and i have the administrator account, all the other accounts in this computer has the downloaded files as well. I don't want to share my downloaded files to the other accounts in this computer, how do i change it to just being saved and downloaded to only MY account and not the other accounts as well?

You can by going to itunes and connect your phone y a usb cord and click on iphone which should be near the upper right hand corner and then back up your phone

Yes download iexplorer then then install and open then