How to transfer music from "itunes for ipad" to "itunes for mac" ?

Howdy lobkel,

I understand that you're looking to transfer content from your iPad to your Mac. If you're looking to transfer content purchased from the iTunes Store, this can be done by using the "Transfer Purchases" feature, or by redownloading the content from the iTunes Store. Both of these methods are detailed in the article linked below.

Redownload or transfer your iTunes Store purchases from an iPhone, iPad or iPod to a computer - Apple Support

Sincerely

Your i-device was not designed for unique storage of your media. It is not a backup device and media transfer was planned with you maintaining a master copy of your media on a computer which is itself independently backed up against loss. To use a device with a different setup you transfer the old library from a computer or a backup directly to the new setup, not the device to the library. Media syncing is one way, computer to device, updating the device content to the content on the computer, not updating or restoring content on a computer. The exception is iTunes Store purchases which can be transferred to a computer.

Redownload or transfer your iTunes Store purchases from an iPhone, iPad or iPod to a computer - https://support.apple.com/en-us/HT201267 - "This feature works only for content bought from the iTunes Store."

For transferring other items from an i-device to a computer you will have to use third party commercial software. See this document by turingtest2: Recovering your iTunes library from your iPod or iOS device - https://discussions.apple.com/docs/DOC-3991 Even this method may not fully recover what you had in the library originally. For example if in order to save space when syncing you had converted music files to a lower bitrate, or photos to a lower resolution, it is those lower quality files you will recover.

Likely this is a feature at the request of the media companies who control whether or not Apple may sell their music and are worried about making it too easy for people (read pirates) to transfer outside sourced files between devices.