password on wireless modem/router

> I need to know where I can find the password for the wireless option.
> [...]

   Someplace on your (unspecified) wireless router?

> [...] I purchased one additional printer but have no more ports at my
> router.

   Buy a cheap network switch, and connect it to your (unspecified)
"my router"?  What is your "my router"?

> Also I purchased a smart Phone [...]

   Not a very detailed description of anything.

> [...] which requires a password to be entered from my moden/Router.

   That's typical of a wireless client device.

> Can someone please tell me where to find the password/ code on the
> moden?

   Nowhere?  It's not a modem (MOdulator/DEModulator) qustion; it's a
wireless router question.

> Model: CM400|DOCSIS 3.0 Cable Modem

   That's a modem only, not a router.  If your (unspecified) router is a
Netgear product, then visit http://netgear.com/support , put in your
(actual) model number, and look for Documentation.  Get the User Manual.
Read.  Look for some topic like "Specify Basic WiFi Settings".