adding values from a text menu and storing them

Projects General Guidance
1

hi i am listing a menu so the user can program the backend with some values

(n): To insert customers name
(p): to insert Customers Phone Number
(1): To Insert Number to text to

so eventually a text will be sent to the number (1) and i will be using the user's name and number as well in the message

these values will be entered just the once and has to be kept stored even after power down

so values n,p, and 1 will be hard coded in to the system once in unless there is a reset to defaults of the program
at the moment i am using

#define Phone6 "0"
#define CustomerName "Users Name"
#define CustomerNumber "MyNUmber"

i can insert the values in to a message but i'm not sure if i can change the values from a menu