Music that I’ve purchased from iTunes won’t download to my iPhone
Do you get any error message when you download?
Do you use the same Apple ID?
Please check the purchase history.
On your iPhone you can check /search:
Go to -> Settings -> tap your profile -> tap Media and purchases -> View account -> log in.
Scroll to and tap -> Purchase history -> tap the last 90 days.
You will then see a list of 'years' and you can select a year to view.
From macOS -> start Music -> tap iTunes Store (side bar) -> show my account -> sign in.
(In the right pane) -> scroll to Purchase history -> tap See All -> tap Last 90 Days, then select a different date range.
Try to redownload music, see -> Related Article: Redownload music
If you still need help, get more help and assistant from Apple directly, see Contact Apple for support and service -> Contact Apple for support and service – Apple Support (UK)