How to reduce the beep noise coming out of an MP3 module for my TDA2030 amplifier circuit project?
You are basically shorting out TDA2030 inputs to ground in AC via C18/C19. You need to add another resistors between pin 1 of each channel (IN+) and half of power supply (R3/R4 and R11/R12). Audio signal goes into pin 1 like you do now from a capacitor.
Look closely at TDA2030 datasheet for single supply schematics.