Here is the full list of all 45 Hogwarts Legacy achievements. It takes around 60-80 hours to unlock all of the achievements on Windows.
Find the Map Chamber as a Slytherin
Find the Map Chamber as a Gryffindor
Find the Map Chamber as a Ravenclaw
Use Ancient Magic on every enemy in the game
Breed every type of beast
Win the House Cup
Grow every type of plant
Spend all Talent Points
Reach Level 40
Complete all collections
Complete all Merlin Trials
Upgrade a piece of gear 3 times
Use Flipendo ten times – to tip one cow or several
Defeat enemies in all battle arenas
Reach the highest point in the castle, the Headmaster's upper study
Find all Demiguise statues
Complete Natsai Onai's relationship line
Complete Sebastian Sallow's relationship line
Complete Poppy Sweeting's relationship line
Defeat Ranrok
Subdue the Lord of the Shore
View all Pensieve memories
Complete all side quests
Beat Imelda's time in all broom races
Unlock all Floo Flames
Discover all cairn dungeons
Rescue the phoenix
Visit Poidsear Coast
Wield a Deathly Hallow
Learn all spells
Save a dragon
Defeat a total of fifty enemies using Petrificus Totalus
Brew every type of potion
Stun 10 different enemies using a Mandrake
Upgrade a piece of gear
Complete all tiers of a challenge
Meet Charles Rookwood in the Map Chamber
Reach a combo of 100
Follow butterflies to a treasure
Spend 5 Talent Points
Find the Map Chamber as a Hufflepuff
Invoke Ancient Magic for the first time
Survive the troll attack on Hogsmeade
Attend your first class
Complete the introduction and finish the Sorting Ceremony