Update List , update the pdf name in the folder , attach these file

Hello Team,

  1. I am having a List - with the Invoice numbers in it.
    2.One data table (this data table has many columns- but i am focusing on 2 columns - Invoic no, Order number)
  2. there is a folder having the .pdf files with these invoice numbers.
  3. I have to change these invoice names in the folder with the new names based on the value in the column - “Order Ref”

Planning to use the - Linq Queries…
how shall i do this??

Can any one please help me