How do I transfer a music album from iTunes on Mac to my wife's iPhone and iPad?

Downloaded from where exactly?

If this is a purchase from the iTunes Store, you can use Family Sharing so she can access it on her devices

click here ➜ How to download apps and content that your family members purchased - Apple Support

If this is a CD you ripped, you can try to sync it, but unless your Mac also holds her own music library, the sync will erase her music content on her devices and replace it with yours.

If this is from a different source than either of the 2 above, then it will depend on the source whether its shareable or not.

Response to Peter Friend

Hello Peter ,

On your Mac , select the album , share , then Airdrop . The album will be dropped into the iTunes library on the iPhone . In General settings , check that Airdrop is enabled on both the Mac & the phone first .

🖥️ 📱