Re: PIC16F1827 - UART 3.3V
Depending on what else you are doing with it you could just run the PIC from 3.3V and get compatibility that way.
If you do need the PIC to run from 5V then you need to determine if your module is "5v tolerant", meaning that its input can withstand 5V from the PIC. Many can as it is a common problem. If not then a resistor voltage divider might work, something like 20K series 10K to ground, giving a 3:2 reduction.
In the other direction a 3.3V signal to a 5V PIC USART is going to be technically out of spec as the input is "CMOS" but will probably work anyway, at least at low speeds.