How to pass parent package varibale value to child package

SSIS and Import/Export
1

Hi All
I am looking for solution to pass parent package variable to child package and
use that value in child package.I am using SQL Server 2012.

2

Did you google it? Instructions are all over the net:

Use the Values of Variables and Parameters in a Child Package

3

You probably need to use the Parameters to do that. Create the parameters at the Project level.