How to Add an MP3 to iPhone
Apple's iTunes Store sells music in the AAC (Advanced Audio Coding) format, but you don't need to convert your MP3 files to add them to your iPhone. Both iTunes 12 on your computer and the Music app on iOS 8 can play MP3s, so import your music to iTunes and sync your phone to transfer the songs. You can also add individual songs from your iTunes library to the phone without changing its music sync settings.
Add to iTunes and Sync Music
Open the **File** menu in iTunes on your computer and click **Add File to Library** to pick an MP3 to add. If you can't see the menus, press **Ctrl-B**.
Plug in your iPhone with the USB cable and click its icon on the iTunes toolbar. Switch to the **Music** tab. If **Sync Music** isn't checked, enable it.
Pick either **Entire Music Library** to copy all songs from iTunes to your phone, or **Selected Playlists, Artists, Albums and Genres** to pick and choose from your library.When using the latter option, check the box by each item you want to include. Watch the meter at the bottom of the window to see how much space your iPhone has left.
Click **Apply** to copy the selected music to your iPhone.
Add Individual Songs to an iPhone
Plug in your iPhone and click its icon in iTunes. On the Summary tab, check the **Manually Manage Music and Videos** option if it isn't already enabled, and click **Apply**.
Open your iTunes music library and select **Songs** from the category selector in the upper-right corner.
Select the songs you want to add and begin dragging them to the left to open a sidebar that shows connected devices. Drag the songs onto the **iPhone** entry in the sidebar and release the mouse button to copy the files to your phone.
Tips & Warnings
- You can also add MP3 files to iTunes by dragging them from Windows into the iTunes library.
- If your phone can't fit all of the songs you want, iTunes displays an error message. Switch to using selected items or pick fewer songs.
- IPhones can sync music from only one computer at a time. If you plug your phone into a friend's computer and turn on "Sync Music," your phone erases all the music you synced from your home computer.