Nrf24l01 addresses

What are some of the addresses that I may be able to use? Can it be virtually anything, like perhaps my name? Or something else like a set of numbers?

And just because it's 5 byte addresses, does it have to be 5 characters long? I have seen some people do their addresses in something that looks like hex

Just asking

An address is up to 5 bytes - any 5 bytes. You can express those bytes in decimal, hex or binary. I just use characters as it makes it easier for me to read.

Have a look at this Simple nRF24L01+ Tutorial