The "CashAddr" format was developed by the Bitcoin Cash team to encode addresses in a format to reduce user error when sending and receiving Bitcoin Cash. This new format helps distinguish between Bitcoin Cash (BCH) and Bitcoin (BTC) addresses.
CashAddr BCH address format, like this example:
The prefix bitcoincash indicates the network type, which can be added or not added without affecting transfers.
Since Bitcoin Cash is a fork of the Bitcoin blockchain, its address format used to be similar to that of Bitcoin, called Legacy address. It starts with number 1 or 3 and is case sensitive. Many exchanges use addresses that start with number 1.
BitPay address is powered by BitPay company, which has not been widely accepted and has been abandoned.