Doubts regarding the excel sheet provided

Hi In the 'event_name' column, we have "-" and "Don't want to say". Do I need to consider them as missing values or they are categories of the column? And if we consider them as categories of the column, do I include them in the data analysis process? In the "Post Name" column, we have "-". Do I need to consider it as missing value or is it a category of the column? Also "c-10" seems like typo. Can I change it to "c10" in the same column? Also any changes in the excel sheet during data preprocessing, do I need to show it in the report and the excel sheet that will be hyperlinked? Like if I delete a row with missing value or replace it with some other value or removing rows with outliers?