Both platforms require Parental Advisory tags applied through a dedicated metadata field — never written directly into the title.
2.12.1 When to flag Explicit
Flag content as Explicit when it contains profanity, sexually explicit themes, graphic violence, or adult content. Apple displays a Parental Advisory badge automatically; Spotify displays an "E" icon next to the track. Neither badge should be duplicated into the title text — Apple explicitly bans "(Explicit)", "(Explicit Version)", "(Dirty)", and "(Dirty Version)" from titles.
2.12.2 The Clean flag has a specific, narrow meaning
Apple's standard: only flag a track Clean if a corresponding Explicit version of the same track exists. The Clean flag does not mean "contains no explicit content" — a track with no explicit material carries no Parental Advisory tag at all, neither Explicit nor Clean. "(Clean)", "(Clean Version)", "(Edited)", and "(Edited Version)" must not appear in titles.
2.12.3 Spotify's parallel rule
Spotify's metadata guide confirms the same structure independently: an explicit track must be tagged Explicit; a clean version of an explicit track must be tagged Clean specifically to prevent customers accidentally purchasing the wrong version; both tags are set via a dedicated metadata field, never as title text.
2.12.4 Submitting explicit words
Submit titles in their original, intended form, including explicit words exactly as the artist intends them. Apple automatically censors explicit words for display (e.g. "F**k"). Do not insert your own asterisks — self-censored submissions reduce listeners' ability to search for and find the content.
Source: MadDesk article 2.12 (2-12)