changing date from text to date

Yeah, I'm pretty sure this is the issue. This uses the optional "culture" argument of Table.TransformColumnTypes to pick the appropriate way of interpreting the date format.

Another way to do this is to tweak the M code directly. If the date format is dd/mm/yyyy, then you can write

Table.TransformColumnTypes(
    #"Split Column by Delimiter",
    {
        {"Item.1", type text},
        {"Item.2", type date},
        {"Item.3", type text},
        {"Sales", type number}
    },
    "en-IN"
)

If the date format is mm/dd/yyy, then use "en-US" for the last argument instead.

(There are plenty of other cultural choices but these are the two I remember for the sake of date interpretation.)