Here is the full list of all 35 A Plague Tale: Innocence achievements. It takes around 12-15 hours to unlock all of the achievements on Windows.
Fully upgrade the sling
Find all curiosities
Find all the gifts for the orphans
Enter through the main door
Play hide-and-seek
Save a soldier
Find a lunch for Hugo
Save the dying
Enter into the 5 alchemist carts
Find all the flowers
Find 13 curiosities
Stay with the captain
Complete all chapters
Complete chapter 16
Find Rodric's forge
Complete chapter 15
Fully upgrade the equipment
Complete chapter 14
Complete chapter 13
Complete chapter 12
Craft 100 ammunitions
Complete chapter 11
Complete chapter 10
Complete chapter 9
Find 6 flowers
Complete chapter 8
Find the tomb
Complete chapter 7
Complete chapter 6
Complete chapter 5
Complete chapter 4
Complete chapter 3
Complete chapter 2
Complete chapter 1
Complete the aiming training