Children are not invited to the wedding: This is very difficult indeed and again should not be mentioned on the invitation. Invitees should actually realise that if their children aren't mentioned by name on the invitation then they're not invited but they probably won't. Friends of the bride and groom may not appreciate that you don't look on their little darlings quite as they do but be firm. Friends with children should be telephoned and politely told that children cannot be catered for. If they are offended, then that's unfortunate.
Wedding invitations are one of the biggest parts of wedding planning. It is how guests are informed about a wedding and how the bride keeps track of the guest count. A wedding invitation is also the first look guests get of your wedding.