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