Identify is a 1st level divination spell from the Basic Rules. The spell is available to the Wizard and Bard, and automatically given to Clerics of the Forge and Knowledge domains.
What does it do?
Identify lets you immediately learn the properties of a magical item, or know what spells are affecting a creature or object.
It takes a minute to cast, and requires a one-time 100 gp investment for the material component, which the spell does not consume. It can be cast as a Ritual, so you can spend an additional ten minutes to cast it without expending a spell slot. If you’re a wizard or bard, you don’t need to have the spell prepared to cast it as a ritual. If you’re a Forge or Knowledge domain cleric, Identify will be a domain spell, so you’ll always have it prepared.
Other ways to identify items
According to the Dungeon Master’s Guide, characters can identify a magic item by spending a short rest with it in their possession. Potions can be identified simply by tasting them. This makes the utility of the Identify spell a little less obvious.
However, Identify works in eleven minutes (or one minute, at the cost of a spell slot) instead of an hour for a short rest. The spell can also identify things you can’t identify by taking a rest. The spell can reveal the properties of basically anything that has been magically created or has a spell affecting it. For example, it can be used to identify a teleportation circle inscribed on the ground. You can also use Identify to learn which spells are currently affecting a creature or object, if any.
Conclusion
Identify is a thoroughly useful utility spell, especially when cast as a ritual. You could cast Identify on every object you encounter without expending a single spell slot. At least one person in your party should know this spell.