Valor Points are a currency that is being readded in Patch 9.0.5 to help players gear up through the Mythic+ system. There are two ways to earn Valor Points: Callings and running Mythic+ dungeons.
Each piece of dungeon gear from Item Level 184 to Item Level 220 that is obtained from Mythic+ Dungeons will be given a Rank from 1 to 12. This rank will be shown on the tooltip of the item. This includes items from the Great Vault, as long as they fall within the range of Item Levels. Upgrading a piece of gear will increase it by one rank.
There are four ranks that require an achievement pre-requisite to progress further.
Upgrading an item that is Item Level 213 (Rank 10) or higher requires  Shadowlands Keystone Master: Season One.
Upgrading an item that is Item Level 207 (Rank 8) or higher requires  Shadowlands Keystone Conqueror: Season One.
Upgrading an item that is Item Level 200 (Rank 6) or higher requires  Shadowlands Keystone Explorer: Season One.
Upgrading an item that is Item Level 197 (Rank 5) or lower requires no achievement.