All doors lock automatically when the lock side is pressed. They unlock when the unlock side is pressed.
Driver's door

Front passenger's door

To lock all the doors from an open front door, press the lock side of the door lock switch and then close the door.
NOTE
When locking the doors this way, be careful not to leave the key inside the vehicle.
Locking, Unlocking with Transmitter
Auto Lock/Unlock FunctionMazda 6 Owners Manual: Automatic transaxle fluid (atf) replacement
Warning
When the transaxle and ATF are hot, they can badly burn you. Turn
off the engine and wait until they are cool before changing the ATF.
1. Remove the oil dipstick.
2. Remove the oil drain plug and washer.
3. Drain the ATF into a container.
4. Install a new washer and the drain ...
Mazda 6 Owners Manual: Child-Restraint System Types
In this owner's manual, explanation of child-restraint systems is provided for the following three types of popular childrestraint systems: infant seat, child seat, booster seat.
NOTE
Installation position is determined by the type of child-restraint system. Always read the manufacturer' ...