Hello,
I am interested in the audio player use case where we read the input from a wave file on a SD card.
I am interested in reading the input from some type of voice input (microphone) and playing it at the same time. I guess the output would stay the same but the input should be a microphone.
I searched a bit but I did not find any east to use option.
Would you please help me (I don't have a strong hardware background so apologies if my question is very basic).
Thanks
Welcome to the forums!
I am not the best person to help you with specifics, but I should think you need to start with a pre-amplifier for the microphone input. The DUE analogue pins can only handle 3.3V, so you need to plan carefully your input!
If the microphone is a non powered type, the output will only be a few mV, if it is a powered microphone, what is the output? If it is more than +-1.5V it will need reducing. You need exactly +-1.5V pk-pk. Look up op-amp microphone amplifier. You will need to bias your analogue pin to half Vcc using a pair of resistors as a potential divider. I could probably design it for you but what fun would that be? 
Have you tried google "arduino due microphone input"? audio - Using a microphone with an Arduino - Electrical Engineering Stack Exchange
That has quite a lot of information which should give you some ideas.
I hope I have helped you in the right direction. One word of warning, the DACs on the DUE are VERY VERY fragile/delicate, do lots of reading articles about DUE audio output before you think of doing ANYTHING with the DACs!!
Good luck 
Graham