m query remove character from column in a table

Hi, I'm very new to Power BI and learning now M language.

My question is: which formula would remove a specific character in a table?

For example, I have this code:

let
Source = Excel.Workbook(File.Contents("my_path.customer.xlsx"), null, true),
Categories_Sheet = Source{[Item="Categories",Kind="Sheet"]}[Data],
#"Promoted Headers" = Table.PromoteHeaders(Categories_Sheet),
#"Changed Type" = Table.TransformColumnTypes(#"Promoted Headers",{{"CategoryID", Int64.Type}, {"CategoryName", type text}, {"Description", type text}, {"Link", type text}}),
Custom2 = Text.Remove(#"Changed Type".[CategoryName],{"o"})
in
Custom2

And I want to remove all "o"s from CategoryName column, so I've written this line:

Custom2 = Text.Remove(#"Changed Type".[CategoryName],{"o"})

but its' not correct.