I have already ordered my save the dates. The only thing I didn't include was 'formal invitation to follow.' I don't know if this is a must, but I feel like I should have it somewhere. Does anyone have an idea of where to include it within the envelope now that the save the dates are already printed? I've thought about putting a clear address label with that phrase on the back of the envelope, but not too sure. Any thoughts or suggestions would be greatly appreciated! Thank you all so much!