Crates are virtual treasure chests that hold a different level of rarity prizes to be won by the people that purchase and unlock them. The majority of crates can be purchased and opened with a key which will also need to be purchased separately using Coins.
To purchase crates you can simply visit the marketplace to purchase crates & keys separately.
Purchase crates and keys by hovering over the item with your mouse cursor. You can also view more details for further information on the item