You can try some sort of ADC (analog to Digital Coder) circuits and then use digital display (even 7-segment with its decoder) or any sort of it.
But the main issue is to convert the incoming AC into a certain form which can be translated to a signal that is proportional to the input AC amplitude.
you can use CS5460 IC it HAS 24 bit adc and you can interfacing directly AC input to the IC with only resistor dividor network and you can get reading in digital format in registers in side IC, SPI inteface can be used for uC interface.
if you can get MIKROC, install the software and check the ADC examples, there is a 5v voltmeter there, you only need to make a few changes to make it read 220v. if you dont understand how ADC works, pls read ADC conversion on this page. Good luck and God bless. https://microchippiclessons.blogspot.com