Code to add values to visible filtered cells

Namaskar Experts
The code till now, has filtered the data in column F with Rows <> Blank, rows which have wrong invoice numbers and need to be changed. The complicated part is that I need to write the code to add below the existing code to replace the visible cells by adding "XX" to the value of Column C in the beginning of the cell value. The easy part is after that I need to remove the colored rows and remove the filter. Hope your expertise will help me to get the expected result as shown in the workbook.
TYIA

The query is solved. Thanks to Glenn Kennedy for referring CHAT GPT.