They started to migrate to a new system 2 years ago, most of the drivers give you a receipt if you ask for it.
And yes, most of the cabs accept credit / debit card.
Just in case, If you gonna take it from the Airport, when you take your bag and go to the main hall, you gonna see a hugeeeeee line, this line is for the cabs.. I would mind to check before where you are going. because most of the times they have a board on the wall showing the prices for different neighborhoods according to the distance!
They also have a bus, if you prefer, with air conditioning and wi-fi.