Here is the full list of all 69 Dragon Age Inquisition achievements. It takes around 80-100 hours to unlock all of the achievements on Windows.
Even Ground on: slay a level 16 or higher Fereldan Frostback.
Slay 10 great bears promoted by Grizzly End.
Rest Easy trial always on in Emprise du Lion: claim Suledin Keep.
Fair-Weather Friends always on: enter Halamshiral with all followers.
Travel Light on for "In Hushed Whispers": finish the quest.
Defeat 1,000 demons in single-player mode.
Enter the heart of the Solasan temple.
Slay 10 high dragons in single-player mode.
Progress the story to unlock.
Unlock all caches watched over by ancient statues.
Find all of the wearable items that make up the Taken Shape.
Recruit a powerful ally to even the score.
Defeat 20 foes promoted by Walk Softly.
Take It Slow on: reach Skyhold at level 5 or less.
Upgrade your alchemic potions, grenades, or tonics 30 times in a single playthrough.
Unlock 15 astrariums in a single playthrough.
Seal 75 rifts in a single playthrough.
Rub Some Dirt on It on: slay the Hivernal high dragon.
Destroy all the Winter Shards and light all the fires in the Old Temple.
Impress the Avvar of Stone-Bear Hold and gain their friendship.
Dispel a myth of ancient days.
Uncover the secrets of a legendary figure.
Become friends with at least three of your inner circle in one playthrough.
Craft an item from Tier 4 materials in all non-masterwork slots in single-player mode.
Discover a campsite and establish at least one Inquisition camp in 10 wilderness areas.
Defeat 2,500 enemies in single-player mode.
Completely upgrade one throne.
Purchase any new decoration element for Skyhold.
Complete 20 requisition requests in a single playthrough.
End the earthquakes threatening the surface.
Help Shaper Valta discover secret dwarven history.
Liberate three keeps in a single playthrough.
End the threat once and for all.
Reach level 20 in single-player mode.
Finish the single-player campaign on at least Hard without lowering the difficulty.
Finish the single-player campaign on Nightmare without lowering the difficulty.
Harvest 50 herbs from Skyhold's garden in a single playthrough.
Reach an ancient ruin before your enemies.
Acquire 10 Inquisition agents in a single playthrough.
Commit to a romantic relationship.
Earn 50,000 or more gold across all single-player playthroughs.
Make an impression on the Orlesian court.
Gain the full approval of the Orlesian court.
Level up the Inquisition to rank 10.
Face your fears in the Fade.
Choose a specialization class.
Complete 50 missions or operations in a single playthrough.
Complete a mission at the expedition table in the Legion of the Dead camp.
Defeat an ogre alpha.
Recruit all possible companions in a single playthrough.
Collect 250 codex entries in a single playthrough.
Kill a high dragon in single-player mode.
Survive an attack on the Inquisition.
Close the Breach.
Purchase or secure five different mounts of any kind.
Spend 10 points in a single ability tree with any one single-player character.
Recruit a new companion.
Land a single blow in excess of 1,000 damage in single-player mode.
Gain access to a major city for the Inquisition.
Discover a veilfire rune.
Complete a timed mission on the war table.
Enchant or upgrade a piece of equipment in single-player mode.
Craft a weapon or piece of armor in single-player mode.
Trigger a cross-class combo with a character you control in single-player mode.
Secure a mount.
Discover a campsite and establish an Inquisition camp in any wilderness area.
Find and recover a shard identified by an ocularum.
Upgrade any ability once in single-player mode.
Finish the prologue.