To sign a card, click the Sign Card button (pencil icon on mobile) and then type your message into the text box. Be sure to click Save when you're done.
If there is no Sign Card button (or pencil icon on mobile), then the delivery time may have already passed. Once a card is delivered (just like with a real card), it's no longer signable as it's in the recipient's hands. We suggest emailing the recipient directly with your message.
If the card hasn't been delivered yet but you can't see the Sign Card button, your firewall may be preventing you from seeing our page. Try logging off VPN if you're using one and access the card again or sign from your phone if your phone isn't on VPN.
If you're not on VPN, then you may have ad-blockers that are blocking our site images. Try disabling your ad-blockers and then visit the card again.