Here is the full list of all 24 Company of Heroes 3 achievements.
Complete the Italy Campaign
Break the Gustav Line
Save Monte Cassino
Silence Anzio Annie
Issue 500 orders in Tactical Pause
Complete Calabria
Win 25 Multiplayer or Skirmish matches
Complete the North Africa Operation
Win a Multiplayer or Skirmish match without losing a Victory Point ticket
Complete a Mission or Skirmish without reinforcing a Squad
Complete a Mission or Skirmish without losing a Squad
Win a Multiplayer or Skirmish match
Use Battlegroup Abilities 100 times
Complete Mission Zero
Issue an order in Tactical Pause
Purchase a Detachment
Gain 100% loyalty with Valenti
Gain 100% loyalty with Buckram
Gain 100% loyalty with Norton
Collect all Soldier Stories
Decide where to go after Salerno
Break the Volturno Line
Uncover a conspiracy
Heal a unit with ice cream