A: Her participation depends on her beliefs and the dogma of your religion. She can kneel or stand when the rest of the congregation does, and should answer "I will" or "I do" when the officiant asks if those assembled will support you and your fiancé. However, she doesn't have to say any prayers or sing hymns if she'd prefer not to. As for Communion, different beliefs have different rules. Often, people who are not receiving Communion can still approach the altar and by crossing their arms over their chest, signify that they would like a blessing, rather than the bread and wine. Talk to your officiant about the convention in your house of worship, and tell your bridesmaid. It's also a good idea to print the information in your program so that guests who belong to different religions or denominations will know what their options are. Each person can then decide for herself what will make her feel most comfortable.