Add dot after each character in string

This will not change data that has dots. If this isn't what you need, provide a complete sample of data and what should be modified. See directions below.

let
    Source = Excel.Workbook(File.Contents("C:\Users\Dante\Desktop\Monthly Country Reports\XXX\test.xlsx"), null, true),
    __activityqty_Sheet = Source{[Item="__activityqty",Kind="Sheet"]}[Data],
    #"Promoted Headers" = Table.PromoteHeaders(__activityqty_Sheet, [PromoteAllScalars=true]),
    #"Changed Type" = Table.TransformColumnTypes(#"Promoted Headers",{{"rel_region", type text}, {"rel_subregion", type text}, {"client", type text}, {"period", Int64.Type}, {"country", type text}, {"xcountry", type text}, {"activity", type text}, {"xactivity", type text},}),
    #"Renamed Columns" = Table.RenameColumns(#"Changed Type",{{"period", "Date"}}),
    #"Duplicated Column" = Table.DuplicateColumn(#"Renamed Columns", "Date", "Date - Copy"),
    #"Reordered Columns" = Table.ReorderColumns(#"Duplicated Column",{"Date", "Date - Copy", "country", "activity", "xactivity",}),
    #"Removed Columns1" = Table.RemoveColumns(#"Reordered Columns",{"Date - Copy"}),
    #"Changed Type1" = Table.TransformColumnTypes(#"Removed Columns1",{{"Date", type text}}),
    #"Added Custom" = Table.AddColumn(#"Changed Type1", "Custom", each Date.FromText(
Text.Range([Date], 0,4) & "-"  &
Text.Range([Date], 4,2)
)),
    #"Changed Type2" = Table.TransformColumnTypes(#"Reordered Columns1",{{"Custom", type date}}),
    #"Removed Columns2" = Table.RemoveColumns(#"Changed Type2",{"Date"}),
    #"Renamed Columns1" = Table.RenameColumns(#"Removed Columns2",{{"country", "CountryCode"}, {"Custom", "Date"},}),
    #"Changed Type3" = Table.TransformColumnTypes(#"Renamed Columns1",{{"CountryCode", type text},}),
    #"Inserted Text Between Delimiters" = Table.AddColumn(#"Changed Type3", "Text Between Delimiters", each Text.BetweenDelimiters([xsip], " ", " ", 1, 3), type text),
    #"Reordered Columns2" = Table.ReorderColumns(#"Inserted Text Between Delimiters",{"Date", "CountryCode", "activity", "xactivity",}),
    #"Removed Columns3" = Table.RemoveColumns(#"Reordered Columns2",{"Text Between Delimiters"}),
    #"Inserted Text After Delimiter" = Table.AddColumn(#"Removed Columns3", "Text After Delimiter", each Text.AfterDelimiter([xsip], " ", 1), type text),
    #"Reordered Columns3" = Table.ReorderColumns(#"Inserted Text After Delimiter",{"Date", "CountryCode", "activity", "xactivity",}),
    #"Removed Columns4" = Table.RemoveColumns(#"Reordered Columns3",{"Text After Delimiter"}),
    #"Reordered Columns4" = Table.ReorderColumns(#"Renamed Columns5",{"Date", "CountryCode", "activity", "xactivity",}),
    #"Renamed Columns6" = Table.RenameColumns(#"Reordered Columns4",{{"activity", "Activity_Code"}}),
    #"Split Column by Positions3" = Table.SplitColumn(#"Renamed Columns6", "xactivity", Splitter.SplitTextByPositions({0, 7}), {"xactivity.1", "xactivity.2"}),
    #"Changed Type7" = Table.TransformColumnTypes(#"Split Column by Positions3",{{"xactivity.1", type text}, {"xactivity.2", type text}}),
    #"Replaced Value2" = Table.ReplaceValue(#"Changed Type7","018","(2018",Replacer.ReplaceText,{"xactivity.2"}),
    #"Replaced Value3" = Table.ReplaceValue(#"Replaced Value2",")D",") D",Replacer.ReplaceText,{"xactivity.2"}),
    #"Replaced Value4" = Table.ReplaceValue(#"Replaced Value3",")T",") T",Replacer.ReplaceText,{"xactivity.2"}),
    #"Replaced Value5" = Table.ReplaceValue(#"Replaced Value4","019","(2019",Replacer.ReplaceText,{"xactivity.2"}),
    #"Filtered Rows1" = Table.SelectRows(#"Replaced Value5", each true),
    #"Replaced Value6" = Table.ReplaceValue(#"Filtered Rows1"," #(tab)Leadership","Leadership",Replacer.ReplaceText,{"xactivity.2"}),
    #"Replaced Value7" = Table.ReplaceValue(#"Replaced Value6"," Crow","Crow",Replacer.ReplaceText,{"xactivity.2"}),
    #"Replaced Value13" = Table.ReplaceValue(#"Replaced Value12"," (2","",Replacer.ReplaceText,{"xactivity.1"}),
    #"Filtered Rows2" = Table.SelectRows(#"Replaced Value13", each true),
    #"Trimmed Text" = Table.TransformColumns(#"Filtered Rows2",{{"xactivity.2", Text.Trim, type text}}),
    #"Renamed Columns8" = Table.RenameColumns(#"Changed Type8",{{"xactivity.1", "ActivityID"}}),
    #"Filtered Rows4" = Table.SelectRows(#"Trimmed Text1", each true),
    #"Removed Columns" = Table.RemoveColumns(#"Filtered Rows4",{"rel_region", "rel_subregion", "client", "xcountry"}),
    #"Added DotValues" = 
		Table.AddColumn(
            #"Removed Columns",
            "With Dots",
            each
                let
                    varLength = Text.Length([Data]),
                    varData = [Data]
                in
            if Text.Contains(varData, ".") then varData
            else
                Text.BeforeDelimiter(
                    Text.Combine(
                        List.Generate(
                            ()=> [x=0],
                            each [x] < varLength,
                            each [x = [x]+1],
                            each Text.Middle(varData, [x], 1) & "."
                        )
                    ),
                    ".", varLength-1
            ),
            type text
        )
in
    #"Added DotValues"

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How to provide sample data in the Power BI Forum - Provide data in a table format per the link, or share an Excel/CSV file via OneDrive, Dropbox, etc.. Provide expected output using a screenshot of Excel or other image. Do not provide a screenshot of the source data. I cannot paste an image into Power BI tables.