I've try to make a AM/FM transmitter and i have a problem :/ .... it has a distortion.. can some one help me?

https://makezine.com/projects/super-simple-fm-transmitter/
https://makerf.com/posts/fun_with_crystal_oscillators_part_3

 

also i like to make a amplifier but I've read something about in jack stereo to mono?

 

Super Simple usually means super poor quality (distortion).
Your circuit has nothing like a volume control so the input audio signal level might be too high. The polarity of C6 is backwards.
Your amplifier is missing the very important capacitor in series with a resistor at the output pin 5 of the LM386 to ground.
Is your battery 9V?
Will your crystal oscillator work when its Vcc is from about +3V to about +6V?

 

I've already change the polarity of the C6 in the PCB, the crystal I've use is a EPSON brand, and its hard to find a crystal oscillator in the philippines and it might be work +3V to +5V (http://docs-asia.electrocomponents.com/webdocs/1516/0900766b8151652c.pdf)

my supply is 9V battery.

what is missing in LM386?

 

You've got the resistor/capacitor on pin 5 of the LM386 on the 'transmitter' schematic, but these are missing on the 'amplifier' schematic.

You don't say if it is the AM or FM transmitter that sounds distorted. If it is the FM section, then it is most likely too much audio input. If it is the AM section..... well, I don't know of any oscillator modules that will modulate linearly by varying the Vcc.