You have a digital card and a person to send it to. Should it go by WhatsApp or by e-mail? Both are fine, and a good plan uses both: WhatsApp to collect, e-mail to deliver.
Which is better for collecting messages?
WhatsApp, or any chat the group already uses. A link in a chat gets read within hours. Post it once, add the deadline, and send one reminder two days before.

Which is better for delivering the card?
E-mail. A card by e-mail can be read on any device, opened again later and stored. A card in a chat is easily lost. Delivery by e-mail also lets you schedule the exact day and time.

Can I send a card to a mobile number?
Cards are delivered to an e-mail address. If you only have a number, ask for the address or send the link by chat and let the person open it.

How do I stop people forgetting?
- Give a clear deadline, not “soon”.
- Tell people what to write: a memory and a wish.
- Send one reminder, not five.
Is it safe to share the link in a group chat?
The writing link only lets people add a message; the card is only visible to the receiver and the organiser. Do not post the link where the receiver can see it, if it is a surprise.
Can I send an e-card by WhatsApp?
You share the writing link in WhatsApp so everybody can write. The card itself reaches the recipient by e-mail on the chosen day, and the recipient can forward the link afterwards.
What if not everybody has an e-mail address?
That is no problem for the writers: they only need the link, not an e-mail address. Only the recipient needs an address, or somebody who forwards the link.
Collect in the chat, deliver by e-mail
Make a card, share the link in your chat and let it arrive by e-mail on the day.