Depends on the congregation a bit.
In our last congregation while I was growing up we never got ANY sheperding calls. The elders only did sheperding calls if they think you messed up.
But then we moved to a new hall and they did sheperding calls on everyone at LEAST twice a year no matter what. They'd usually ask how everyone was doing, if they had any questions or concerns, if there were any goals the elders could help you reach. etc.
If your wife is in a congregation where they are routine then she should expect them to pray with her, read a few scriptures. They'll probably have a REALLY short prepared talk or article they want to read with her. Then they'll ask her what her spiritual goals are. Odds are she'll make something up real quick to avoid looking like she doesn't have any goals. And then they'll try to help her reach it.
So if she says she wants to conduct a bible study, they'll probably arrange for a pioneer to hand a bible study off to her in a few weeks. So 'be careful what you wish for' they might help you get it.
The whole thing normall only takes about 15 minutes.