Solemn Authority is a Continuous Trap Card.
Trap Cards are normally Set first and can be activated on a later turn, often in response to an action.
On the current TCG and OCG Forbidden & Limited lists tracked here, Solemn Authority is Unlimited.
YGOPRODeck lists Solemn Authority for these formats: Duel Links, Common Charity, Speed Duel, TCG, OCG, Master Duel.
Solemn Authority belongs to the Solemn archetype—use that tag when searching for engine pieces and tech options.
A listed print of Solemn Authority appears in Legendary Collection 5D's Mega Pack (LC5D-EN197) at Common rarity.
Among markets shown on this page, the lowest listed snapshot for Solemn Authority is about $0.08 on Cardmarket (prices change frequently).
