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