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.
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.
Craft an item from Tier 4 materials in all non-masterwork slots in single-player mode.
End the earthquakes threatening the surface.
Help Shaper Valta discover secret dwarven history.
Defeat 20 foes promoted by Walk Softly.
Complete a mission at the expedition table in the Legion of the Dead camp.
Defeat an ogre alpha.
Impress the Avvar of Stone-Bear Hold and gain their friendship.
Dispel a myth of ancient days.
Uncover the secrets of a legendary figure.
Destroy all the Winter Shards and light all the fires in the Old Temple.
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.
Slay 10 great bears promoted by Grizzly End.
Enter the heart of the Solasan temple.
Slay 10 high dragons in single-player mode.
Rub Some Dirt on It on: slay the Hivernal high dragon.
Purchase any new decoration element for Skyhold.
Defeat 1,000 demons in single-player mode.
Seal 75 rifts in a single playthrough.
Rest Easy trial always on in Emprise du Lion: claim Suledin Keep.
Liberate three keeps in a single playthrough.
Discover a campsite and establish at least one Inquisition camp in 10 wilderness areas.
Recruit a powerful ally to even the score.
Reach an ancient ruin before your enemies.
Reach level 20 in single-player mode.
Unlock 15 astrariums in a single playthrough.
Defeat 2,500 enemies in single-player mode.
Become friends with at least three of your inner circle in one playthrough.
Commit to a romantic relationship.
Harvest 50 herbs from Skyhold's garden in a single playthrough.
Earn 50,000 or more gold across all single-player playthroughs.
Upgrade your alchemic potions, grenades, or tonics 30 times in a single playthrough.
Completely upgrade one throne.
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.
Kill a high dragon in single-player mode.
Even Ground on: slay a level 16 or higher Fereldan Frostback.
Level up the Inquisition to rank 10.
Face your fears in the Fade.
Acquire 10 Inquisition agents in a single playthrough.
Choose a specialization class.
Complete 20 requisition requests in a single playthrough.
Complete 50 missions or operations in a single playthrough.
Collect 250 codex entries in a single playthrough.
Survive an attack on the Inquisition.
Recruit all possible companions in a single playthrough.
Close the Breach.
Purchase or secure five different mounts of any kind.
Craft a weapon or piece of armor in single-player mode.
Travel Light on for "In Hushed Whispers": finish the quest.
Land a single blow in excess of 1,000 damage in single-player mode.
Spend 10 points in a single ability tree with any one single-player character.
Recruit a new companion.
Gain access to a major city for the Inquisition.
Secure a mount.
Discover a veilfire rune.
Find and recover a shard identified by an ocularum.
Upgrade any ability once in single-player mode.
Trigger a cross-class combo with a character you control in single-player mode.
Discover a campsite and establish an Inquisition camp in any wilderness area.
Complete a timed mission on the war table.
Enchant or upgrade a piece of equipment in single-player mode.
Finish the prologue.