N400 for Family or Individual

[ansa2000]

Our family needs to start the Naturalization process. Will really appreciate of someone can help me with following questions:

1. I have adult children (on green card with us). Do my wife, my son and myself have to fill separate N400 forms?
If we have to do separate online applications, is there a way to connect applications so we can go through this process as a family.

2. Is it better to fill N400 forms online ?

Thanks