I wonder if there is a way to setup parameters to a PIC based device.

One way would be to force the user to connect the device to a PC through a serial cable and on the PC a terminal program can do the configuration. But this is a bit old school...

The idea is to use a WiFi module placed temporary on the device that will communicate through serial port of the PIC. The WiFi module will work as access point and a mobile phone will connect to it.

On the phone, a terminal program may run and do the configuration.

I hope that there exist such terminal programs on mobile phones and avoid making an app to do the config (besides I do not know how to do that app).

Is this idea doable?