If purchased iPad from America as possible work in Egypt and what the carrier

AT&T model iPad uses the GSM protocol and has a mini-sim card slot. GSM is the most widely used protocol.

Here are the converage maps:

For GSM: http://www.worldtimezone.com/gsm.html

( Most people recommend GSM for the widest world wide coverage. )

The other main protocol is CDMA.

For CDMA: http://www.cdg.org/worldwide/index.asp

( The coverage map is optimistic. One company with one cell tower means that the country has coverage. )