What digital actually solves
A digital invitation removes three sources of error at once. It doesn't get left in a bag, it can't get lost between school and the kitchen counter, and it lets the parent answer the second they read it — while they still have the phone in hand and their mind on the task. The last one is the most important. The gap between "reading the invitation" and "answering it" is where most responses disappear.
The eight things the invitation must include
The child's name and age. Date and time, both start and end — parents plan the day around pickup time. Venue with address. Who you are, i.e. "Kari, Ola's mom", so they know who's asking. Your mobile number. A reply deadline. Whether food will be served. And finally what happens with pickup: should parents stay, or drop off and collect? Miss any of this and you get questions instead of answers, and every question is a new delay.
SMS, email or group chat?
SMS gets through and gets read. Email lands in an inbox parents check at work, not when they're planning weekends, and gets lost easily. The group chat is worst for responses because no one feels the question is directed at them. Send SMS to one parent per family. It's also the only format where you can easily see who you've heard from.
Share without spreading more than necessary
A guest list contains children's names and parents' phone numbers. That's not something you should post in an open group or upload to a service without reason. Keep the list on your own phone, send each family their own link, and leave it at that. An invitation link is as private as the message you send it in — it doesn't belong in a Facebook group, but in an SMS to one recipient.
When paper is still the right choice
If your child wants to hand out invitations themselves, that’s part of the fun and they should be allowed to. It doesn’t have to be either-or: let the child give out a slip at preschool or in class, then send the digital invite to the parents the same evening. The slip creates the excitement, the message handles the logistics. You get both, and the replies still come in.