Q:

How to create new order in Kentico from my site?

Am totally new to Kentico i created E-commerce site and want to use API to create orders. can any one tell me which method i should use??, also want to ask if any one tried to display kentico website on Sharepoint application.

A:

Creating an order is a little more complex as you need to get the Customer, Currency, Shipping address, Product and other possibly related objects. A simple example can look like this:
// Gets the first customer whose last name is 'Smith'
CustomerInfo customer = CustomerInfoProvider.GetCustomers()
                                            .WhereEquals("CustomerLastName", "Smith")
                                            .FirstObject;

// Prepares the order addresses
OrderAddressInfo orderBillingAddress = null;
OrderAddressInfo orderShippingAddress = null;

// Gets the customer's address
AddressInfo customerAddress = AddressInfoProvider.GetAddresses()
                                                    .WhereEquals("AddressCustomerID", customer.CustomerID)
                                                    .FirstObject;

if (customerAddress != null)
{
    // Gets the data from the customer's address
    orderBillingAddress = OrderAddressInfoProvider.CreateOrderAddressInfo(customerAddress);
    orderShippingAddress = OrderAddressInfoProvider.CreateOrderAddressInfo(customerAddress);

    // Sets the order addresses
    OrderAddressInfoProvider.SetAddressInfo(orderBillingAddress);
    OrderAddressInfoProvider.SetAddressInfo(orderShippingAddress);
}

// Gets a status for the order
OrderStatusInfo orderStatus = OrderStatusInfoProvider.GetOrderStatusInfo("NewStatus", SiteContext.CurrentSiteName);

// Gets a currency for the order
CurrencyInfo currency = CurrencyInfoProvider.GetCurrencyInfo("NewCurrency", SiteContext.CurrentSiteName);

if ((customer != null) && (orderStatus != null) && (currency != null) && (orderBillingAddress != null))
{
    // Creates a new order object and sets its properties
    OrderInfo newOrder = new OrderInfo
    {
        OrderInvoiceNumber = "1",
        OrderBillingAddress = orderBillingAddress,
        OrderShippingAddress = orderShippingAddress,
        OrderTotalPrice = 200,
        OrderTotalTax = 30,
        OrderDate = DateTime.Now,
        OrderStatusID = orderStatus.StatusID,
        OrderCustomerID = customer.CustomerID,
        OrderSiteID = SiteContext.CurrentSiteID,
        OrderCurrencyID = currency.CurrencyID
    };

    // Saves the order to the database
    OrderInfoProvider.SetOrderInfo(newOrder);
}

This was taken from Kentico docs which I would really recommend to check out as there are many more examples which you might find useful. 
As for your second question - I'm not quite sure what do you mean by displaying Kentico in a Sharepoint application. Kentico is a standalone ASP Web forms application that needs to run on a IIS and cannot by itself be embedded in a Sharepoint. 

