My gift card email didn't arrive

Shopify sends the gift card email, not the theme. It goes out once the order is paid, usually within a few minutes. A gap of a few minutes is normal.

If it still hasn't landed:

Check the spam or junk folder. Gift card emails often filter there.
Confirm the recipient address was typed correctly at checkout.
If the buyer used the gift form and set a Send on date, the email is scheduled for that day and won't arrive earlier.

To resend it:

In your Shopify admin, open Orders and find the gift card order.
Open the gift card and resend the notification from there.