Here is the full list of all 46 Car Mechanic Simulator 2021 achievements. It takes around 120-150 hours to unlock all of the achievements on Windows.
Fix 150 body parts
Finish 100 orders
Paint 60 cars
Unscrew 10 000 bolts
Renovate and sell 50 cars
Buy 30 cars from junkyard
Buy 30 cars from barn
Visit Barn 30 times
Finish path test 25 times
Buy 3000 parts from main shop
Buy 25 cars from impact cars
Sell 1000 parts from inventory
Finish all the special missions
Reach level 50
Buy 5 cars from impact cars
Balance 50 tires
Unlock 10 parking alleys
Swap engine
Fix 50 body parts
Earn 2000 scrap parts
Unlock all upgrades
Reach level 3 of garage expansion
Paint 5 cars
Fix 150 car parts
Buy new car in car salon
Visit Salon
Finish lap with time under 1:50
Buy 1 car from junkyard
Visit a junkyard
Finish test track
Pour old oil on the floor
Renovate and sell 1 car
Earn 5000 CR on sell cars
Earn 50 000 CR on sell cars
Fix 50 car parts
Reach level 20
Buy 1 car from barn
Visit Barn first time
Finish path test first time
Earn 500 scrap parts
Balance 5 tires
Reach level 5
Buy 100 parts from main shop
Finish order with money bonus
Finish 1 order
Finish order with experience bonus