Q: Uploading MP3's doesn't work with iCloud Music Library

Hi Miskyee,

Fortunately iCloud Music Library does support personally created content as well as playlists. If you don't see your content and your playlists from iTunes on your computer, you may need to verify that iCloud Music Library is enabled in iTunes under the same Apple ID as that which is enabled on your iPad.

Your music library includes: 

• songs, albums, and playlists that you added from the Apple Music catalog;
• music that you bought from iTunes; and
• music from other sources in iTunes on your Mac or PC, including CDs that you ripped and music that you created yourself.

Sync Apple Music across your iPhone, iPad, iPod touch and computer
https://support.apple.com/en-us/HT204926

Cheers!