paying for the metro or bus

sherryjb, here is a recent post that may help you.

Which card to use on the Paris metro

No, it's not possible to pay directly with a card (credit or debit), whether it's a physical card or a digital one on your phone (Apple Pay, Google Wallet, etc.).
You need a pass of some sort, either a physical one or a digital one on your phone, to which you then load the correct tickets for your ride.

Sherry, if you have an Apple Phone, all you have to do is go into Wallet, at the top right hand corner click on the + sign. It will be a menu called "Add to Wallet". Scroll down to Transit Card and click on it. Scroll through the menu to France and click on Navigo. It will create a digital Navigo card and walk you through adding money to it. It worked well for me.

Thank you for this tip on the Wallet.. I followed the steps and added France and the Navigo card. I had downloaded the Bonjour RATP and IDF Mobilites apps..looks like I won't need these apps anymore.

I used a physical Navigo card a couple weeks ago (you buy one from a staff person in a metro station for 2 euros). Once you have the card, you can reload it at machines in the stations. I prefer a physical card so that I don’t have to have my expensive phone out in crowded areas. Losing a card would be a lot less of a problem than losing my phone! However, I know many people like using their phone for this kind of purpose.

Keep in mind that you don’t actually load MONEY onto either type of card, you load TICKETS. This is an important distinction because the metro costs €2.5 and buses cost €2 - the tickets are loaded onto your card separately. I found this out the hard way when I boarded a bus and only had metro tickets on my card. The bus would not accept my payment.

Even if you use a digital card, you may find the Boujour RATP useful. You can plan routes on it, look up schedules, etc. If you have a physical card, it will scan it and tell you where you’ve used it and how many tickets you still have loaded.

Navigo Easy cards are available in the ticket machines. No staff person necessary.

100% you can. If you go into your apple wallet you can add "Navigo" and use that to buy tickets. Its not as easy as London or NYC, but its better than managing paper tickets.

Giuliano,
I believe the OP was asking if he could directly use his debit card or credit card (on his apple phone wallet, without a Navigo card), like a charge direct to his account. No, he must have a Navigo card on his phone. That can be loaded from his credit or debit card.