It's no longer a legal requirement to wear a face covering on public transport in England, Scotland or Wales. We do encourage you to wear a face covering in crowded spaces, if you can. For the latest travelling safely information for England, Wales and Scotland, see our Coronavirus page.
Usually, yes you can. It just needs to be a Visa or Mastercard card. Unfortunately, some international card companies don't let you pay contactless on public transport. Just check with them before you travel if you're unsure.