The Destiny 2 Mobile Companion is an amalgamation of many utility features that allow players to keep track and plan their Destiny 2 experience without being logged into the game on their console of choice or PC.

The landing screen of the app, also titled as Companion, serves as the overview of what is going on with the game as a whole, and what is available specifically for the player viewing it.

This screen and its features are meant to answer the question, "What can I do next?" without having to specifically dictate anything. Players are given the status of their quests, vendors, inventory, or general progression so they can make an informed decision that is still within the realm of what they're in the mood for.

The first sections of information to greet players are the news feed and the player's current Milestones to meet.

The news feed is the same for all users, as it is sourced from what the marketing and community teams decide to put out as needed. This will include content roadmaps, patch notes, and the weekly update from Bungie.

Milestones are various tasks. challenges, quests, and events assigned to players based off of current level, in game faction reputation, etc. Currently, this data is read-only but will update immediately as items are completed in the game. All of these items are set up by designers on the game's side and can be added to or modified in updates without the need for modifications on the app's end. 

Milestones can even vary from character-to-character for the same player. Thus the character information at the top center of the screen allows players to switch between characters to see what different Milestones, Triumphs, Collections, and Vendor statuses are available.

The Triumphs system in the Companion App is a mobile mirror of the Triumphs feature that exists now in Destiny 2. Originally a far simpler version of Triumphs only existed on Bungie.net and the Companion App in the original Destiny.

Triumphs serve as a way to commemorate time spent in Destiny 2, tracking all activity from raid completions, to combatants defeated, and events completed. There are seven major themes of Triumphs and a total score at the top.

Within each theme are categories. In the Lore theme, these would be topics on interest. In the Destinations theme, the categories would simply be the names of each destination in the game. Each category will have more granular sections that will then have specific tasks listed out for completion. Within most categories there will be unknown entries that give no information until a player reaches a needed threshold in the game.

As many of these sections have long lists of items, players may sort them as desired.

Below the seven major themes are the Seals; marks of accomplishment that are completed as progression accumulates within the seven themes, along with specific challenging tasks unique to the Seal. When a Seal is completed, players are granted in-game titles to show off their mastery of Destiny 2. Because what it takes to complete a Seal isn't one-to-one with completion of the seven major themes, so tracking them is still necessary.

Destiny 2 Collections is an item directory that also exists in the game. It shows players which items they have earned and have yet to earn. Essentially, anything that can pass through a player's inventory will show up here. Even if a player has removed an item from their inventory permanently, a record of the item having been collected will show up here.

The six major categories have subcategories, and then detailed lists of items for players to track. Highlighted items are what have been collected already. Unless the item is marked as "unknown" players may inspect the details of all items within these lists. "Unknown" items are marked as such because the game designers did not want their existence known to a player until they come across it in the game. Once they do, the app will update to show its information.

Badges are achievements consisting of items specific to a specific expansion or activity. Completion of several of these badges are actually needed to complete some of the aforementioned Seals within the Triumphs feature.

Badges are categorized by class for anything involving Armor, as it is all class-specific. Whereas all other items, weapons, ghosts, etc., can be used by all classes.

In-game vendors provide players items to purchase should they have the necessary reputation level with the NPC or the NPC's associated faction. Players will acquire faction items (loot from downed combatants) as they play that they may turn in to reach a repeating threshold that grants them a reward. The more rewards the player acquires, the higher the reputation with the vendor is, and thus more items are available for purchase. 

Quite often, players will have many of these faction items sitting in their inventories. The vendors section will show players how many items they have on hand and if it's enough to immediately get a reward. 

This guide serves as a valuable utility as not all vendors are in the same location in Destiny 2. Most are located on their own destination while the rest are in the Tower social space. Players can plan what they may do next or which destination they may go to first based off of this information.