Alright, considering ANBU black ops are supposedly secretive, no one in the village other than relatives, the Kage and other ANBU will know that you are ANBU; to everyone else your Rank would be Jounin. When you are acting as an ANBU, masks must be worn and do not give away who you are beneath the mask.
ANBU members may have standard teams of Genin and such to further show their fake Jounin status, their team members are not allowed to know you are ANBU. There will be no set ANBU squads and the Kage will pick who to put on the high class missions from the Batch of ANBU in their village.
In your Profile Area ANBU are required to put in a Codename of Their Choosing, while on ANBU missions or acting as ANBU your Codename is who you are, Code-names should just be one word and don't make it long.
Also, remember that your character cannot simply know that an ANBU is in fact an ANBU; to you and everyone else, they are assumed to be jounin, unless you have worked out some underlying character development plot.