A multimeter is an important device for those who deal with electrical circuits and appliances to get accurate results.
The Multimeter AC symbol helps to identify the type of wiring used in an electrical circuit. For a better understanding of the AC Symbol, you need to know about AC voltage, AC millivolts, and AC; so that you can operate it correctly.

We will discuss the AC voltage, AC millivolts, and AC in this guide.
AC Voltage
AC voltage helps detect the voltage. It is represented by a capital V with a wavy line shown on the device. If you want to measure the voltage of the object, it is necessary to move the dial to the symbol shown on the device. It is recommended to use this device while measuring the AC voltage to detect the proper results.(1)
AC Millivolts
It is represented by mV having three hyphens and a straight line at the top. This symbol stands for milli-voltage and should only be used for measuring the AC voltage of low quality. It is preferable in a smaller circuit. You can measure the millivolts using a multimeter and a voltmeter.
Plugin the red probe into the hole marked as V or + on the meter. Plug the black probe into the hole marked as COM or – on the meter. Turn on the dial on the meter for millivolt range settings and turn on the meter. Hold the insulated handles of probes to avoid inconvenience. You can also measure the DC millivolts for smaller circuits through this device. Dial the point to the AC millivolts symbol and press the function button. The symbol resides beside the mV symbol represented by a yellow symbol.(2)

AC
You can measure AC which is represented by a capital V having a wavy line at the top. This symbol is for current and you can use it for measuring the AC. You can also measure the DC through this. It is represented by the symbol of capital V with three hyphens and a straight line on top. The symbol stands for current and can be used for measuring the DC. Multimeter AC symbols are helpful to detect the accurate readings of AC voltages, millivolts, and current. It also helps to detect the DC, voltages, and millivolts using the same multimeter AC device with some slight changes and deflection.
References
(1) AC Info – https://www.allaboutcircuits.com/textbook/alternating-current/chpt-1/what-is-alternating-current-ac/
(2) Multimeter Info – https://www.electrical4u.com/voltage-or-electric-potential-difference/