Featured and guest artists must be credited through a dedicated field, with precise formatting rules — and never inserted directly into the artist name field or, on Spotify, the version field.
2.7.1 The dedicated field requirement
Featured artists belong in the Featured Artist credit field, never the Primary Artist name field. Each featured artist is listed as a separate entry; do not combine multiple featured artists into one field.
2.7.2 Formatting "feat." in titles (Apple)
When referenced in the title, use lowercase "feat." in parentheses, in English, not localised: "Raat (feat. Neha Kakkar)". Do not use "Featuring", "FT.", "ft.", "Feat.", or "w/". For multiple featured artists: "feat. Artist A & Artist B" or "feat. Artist A, Artist B & Artist C".
2.7.3 Spotify's rule is stricter
Spotify's metadata guide states featured or collaborating artist names must not be referenced in product or track titles, or in product or track version fields, at all. Where Apple permits a correctly formatted "(feat. X)" in the title, Spotify's own guidance points toward using the dedicated artist-role field exclusively rather than the title text.
2.7.4 Avoiding duplicate display
Per Apple's documentation, if Featuring or With roles are used in the initial delivery, the featured artist name is automatically added to the displayed title by Apple Music itself. Manually adding "(feat. X)" to the title AND populating the credit field causes a duplicate. Use the dedicated field and let the platform compose the display.
2.7.5 Featured artists are never Primary
A featured or "with" artist must not be marked Primary at either album or track level. If the same featured artist appears on every track of a release, they must also be credited at the release level, not only per-track.
Source: MadDesk article 2.7 (2-7)