Excel Power Query Change Data Type

Hi. In Excel Power Query  I connect to a text file data source and automatically see a step called "Changed Type" with the following in the formula. As I haven't changed amy data type why do I get this?

= Table.TransformColumnTypes(Source,{{"InvoiceDate", type datetime}, {"Make", type text}, {"CountryName", type text}, {"IsDealer", Int64.Type}, {"SalePrice", Int64.Type}, {"CostPrice", Int64.Type}, {"TotalDiscount", type number}, {"DeliveryCharge", Int64.Type}, {"SpareParts", Int64.Type}, {"LaborCost", Int64.Type}, {"ClientName", type text}, {"Model", type text}, {"Color", type text}, {"ReportingYear", Int64.Type}, {"ReportingMonth", Int64.Type}, {"Registration_Date", type datetime}, {"VehicleType", type text}, {"InvoiceNumber", type text}, {"CountryISOCode", type text}, {"OuterPostode", type text}, {"Region", type text}})

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