Some questions about using block chain

[lucky60]

Hi guys,

Newbie here and ask questions again:

1. when u open wallet on blockchain, u need enter "Identifier", the "Identifier" is not the address which u send & receive BTC, is it?

2. Does the "Identifier" only use on blockchain wallet or it can also use on other wallet?

3. If the "Identifier" is only use on blockchain wallet, if I create a new account on other wallet web site, How can I use the same address of send & receive BTC? Or it is not compatible with each other？


Thanks a lot, Happy New year！