aspx code-
 
//Step-1//
<div class="textleft">Registration Date :</div>
                        <div class="textmid1">
                            <asp:TextBox ID="txtregDate" runat="server" BorderStyle="Solid" BorderWidth="1" BorderColor="#009933" Width="200px" Height="17px" MaxLength="10"></asp:TextBox>
                                <asp:CalendarExtender ID="CalendarExtender1" OnClientShown="OnClientShown" runat="server" Enabled="true" TargetControlID="txtregDate" Format="dd/MM/yyyy" FirstDayOfWeek="Monday" PopupPosition="TopLeft"></asp:CalendarExtender>
                        </div>

 
Step-2
 
<div class="textmid2">Scheme Duration :</div>
                            <div class="textright">
                                <asp:TextBox ID="txtduration" runat="server" Enabled="false" Font-Bold="true" BorderWidth="1" BorderColor="#009933" Width="80px" Height="17px"></asp:TextBox>    Months</div>
                                

 
Step - 3
 
<div class="textmid2">Maturity Date :</div>
                    <div class="textright">
                        <asp:TextBox ID="txtMaturityDate" runat="server" Enabled="false" BorderWidth="1" BorderColor="#009933" Width="150px" Height="17px"></asp:TextBox></div>
                    

My required date As below for maturity Date-
26/02/2021