EditPage.aspx:

<asp:TextBox ID="TextBox1" runat="server" TextMode="MultiLine"></asp:TextBox>
<br />
<asp:Button ID="buttonPassValue" runat="server" Text="Submit" PostBackUrl="Print.aspx">
</asp:Button>

Print.aspx:

protected void Page_Load(object sender, EventArgs e)
{
    Label1.Text = Request.Form["TextBox1"].ToString();
     Or
    TextBox textValue = (TextBox)PreviousPage.FindControl("TextBox1");
    Label1.Text = textValue.Text;
}

Read: Cross Page posting in ASP.NET 2.0