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.
Save the dying
Stay with the captain
Find all curiosities
Enter into the 5 alchemist carts
Find all the flowers
Find the tomb
Find all the gifts for the orphans
Save a soldier
Play hide-and-seek
Fully upgrade the sling
Enter through the main door
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
Complete chapter 11
Complete chapter 10
Find 13 curiosities
Craft 100 ammunitions
Complete chapter 9
Find 6 flowers
Complete chapter 8
Complete chapter 7
Complete chapter 6
Complete chapter 5
Complete chapter 4
Complete chapter 3
Complete chapter 2
Find a lunch for Hugo
Complete chapter 1
Complete the aiming training