Char* and string conversion from an ESP8266 web server
What you need to do is creating a fixed string, this can be done in two ways:

static:

char ssid[100];


Where 100 is the maximum length ever possible. Note that this will always use up 100 bytes, even if less are used (e.g. your string length is 5.
dynamic:

char* p_ssid = malloc(100);


This way a pointer is created to a dynamically created string that can hold 100 characters. Disadvantage is that using malloc in a microcontroller can cause empty memory 'holes' when freeing/mallocing a lot.

With either way you can than use a normal strncpy or strcpy (in first case use &amp;ssid to get a pointer to the ssid).
Also don't forget to add 1 to the length because of the trailing \0 to denote the string is ended.
Thus for storing 10 characters, you need an 11 char sized array.