Purchased songs won't transfer from my iPhone to iTunes Library on PC

See also Hide and unhide music, movies, TV shows, audiobooks, and books - Apple Support and Redownload apps, music, movies, TV shows, and books - Apple Support. In principle anything that was purchased from the store with your Apple ID can be downloaded directly using iTunes so you don't necessarily need to transfer from the device.

If there is content that wasn't purchased from the store see Recover your iTunes library from your iPod or iOS device - Apple Community.

tt2

Hi Brookiesbest,

Thank you for contacting Apple Support Communities. Based on what you stated, it seems like you do not see all of your songs in the purchased tab.

Were the songs purchased using a different Apple ID?

"If you can't find an item in your purchase history

If you can’t find the item you’re looking for, try these things before you contact Apple.

Find out if a family member purchased the item

If you use Family Sharing, your purchase history shows purchases that you made using your Apple ID, but you won't see what other family members bought. To see what other family members bought, sign in with their Apple ID.

If family members have access to your device, you might want to require a password for every purchase.

To control what kids buy on their own devices, turn on Ask to Buy.

Check if you purchased the item with a different Apple ID

If you don't see an item in your purchase history, you might have been signed in with a different Apple ID when you made the purchase. Sign in with that Apple ID to check if your purchases were billed to that account. 

Sign in with your Apple ID."

See your purchase history for the App Store, iTunes Store, and more

Please don't hesitate to let us know if the steps resolved your issue or if you need additional assistance.

Cheers.