It’s a new content since the 19th of June update.Tap on the "Royale Pass" button from the lobbby.You’ll be guided with the rewards, missions and tradable prizes.The "Free" levels are free to play and you can spend your UC to upgrade to "Elite" or "Elite Plus" levels. You will receive extra rewards and "Elite"/"Elite Plus" exclusive missions once you upgrade. You can only upgrade to either "Elite" or "Elite Plus" and it won’t be refundable.※ After the 0.9.5 update, players can now clear all the missions without upgrading the Royale Pass. However, accomplished mission points can be acquired once upgrading Royale Pass.
PUBG MOBILE GAME GUIDE