Q: How does one put on an invitation that children are not allowed to come to the party?
A: It is understood that only those names appearing on the invitation/envelope are those invited to a party. If you fear some of your guests will nonetheless assume that their children are welcome, then you should be sure to request a reply, not a “regrets only” response, so that when they call you can say, “Oh, I am so happy that you and Tom will be able to be here. . .” Should someone say their children are coming, you should feel comfortable responding that although their child (children) is/are adorable and you would love to include him/her/them, space just doesn’t permit and to make an exception for one family and not others would only cause hurt feelings, but you hope she and her husband/date/fiance will be able to come even though the children can’t be included. That is pretty direct and clear, without being offensive. You can’t write “no children” on the invitation.