You can send emails and push notifications to the members who attended an event from the Members page in the admin.
The trick is scoping the list to one event first, then selecting the members you want to reach.
Step 1. Go to Reports & Imports › Request a Report, find the Attendance Records Report, and click "Available on Members › Attendance view". That opens the Members list in its attendance view.

Step 2. Use the "Event report:" search at the top of the list to find and pick your event. The list now shows only that event's attendees, with their arrival, duration, last seen, and check-in methods.
Step 3. Check the box next to each member you want to reach, or use the checkbox in the header row to take everyone shown on the page.
Step 4. Click "Push" or "Email" at the top of the page.

1. Choose your Audience.
2. Write the Subject.
3. Write the Message. It's a rich text editor — type {{ to pick a variable, or click any token below the editor to insert it at the cursor. Variables are replaced with each recipient's own data on send.
4. Set Send At. It defaults to now; set a future time to schedule delivery.

1. Write the Message. It must be 140 characters or less — a live counter tells you what's left, and there's an emoji picker beside it.
2. Add Media. (Optional) JPG, PNG, or GIF up to 8 MB, or MP4 up to 20 MB.
3. Check "Add a link to this message" to make the push tappable. (Optional) The link can point at an Event, Auction, Prize, or Sweepstakes on your site, or at an external URL.
4. Check "Schedule this message for a later time?" and set Send At to send it later. (Optional)
5. Choose your Audience.
