A better picture

The one labeled angel wings is an opuntia microdasys ( Not sure if the spelling is right lol)

It is best to repot both of these into a fast draining soil and go up into maybe a 3 inch pot with both cacti. If you would like to do a gritty mix, you can search "Al's Gritty Mix" in the search bar and get more information on that or you can do a mixture of 50/50 perlite and cactus and succulent soil. Both of these would do great in your window sill, just keep an eye on them because you don't want them to burn if they weren't already in a sunny area in the store you bought them from. Cacti like their soil to be dry in between waterings. Stick your finger down into the pot and if you feel any moisture, do not water. The Angel Wings cactus does have a fake flower glued to it, so you probably want to remove that. I have done it in the past by using a blow dryer on low and slowly melting the hot glue. You don't want to put the blow dryer very close to the cactus though. Other people may have other suggestions on how to remove the flower. Good luck and enjoy your new cacti! - Sam :)