Add custom column

I want to put a custom column after debit and credit and get it calculated

You will need to copy the data to an external program such as a spreadsheet to do that.

@mahmoud_osman, what are you referring to? What type of transaction? Only journal entries have debits and credits columns. And those are the only entries possible. So what would this custom column be for? What are you trying to calculate? There is probably another method for obtaining whatever results you want.