What is this?
Deutsche Lufthansa had been bailed out by the gov.
It’s now raising money to pay back some of that amount.
Read more here
How?
You can read that above, or in your notification that you got, as a shareholder.
What do I need to do
If you want the super discounted stock for a company that gets bailed out by the gov, accept the offering by clicking the URL in the notification. 
THIS WILL IMMEDIATELY ACCEPT IT, NO GOING BACK.
Here’s what you should see after clicking the URL.
If you don’t want it, then you don’t need to do anything. But note that if you don’t want the privileges, you are giving T212 the right to sell your right to the discount to others, as mentioned in the notification.
Support said that next after agreeing to the offering, on the date specified in the notification T212 will buy the shares for us as agreed. EDIT: look like this was a misinformation from the chat support. They actually don’t have an exact date for when we get the shares (from Lufthansa) but it will be sometime in October.
I had a bug with different share buy price specified in the mobile vs web notification. Contacted support and clarified which one was the correct price. Might be different for you.
Disclaimer: I just compiled some of the info present in the notification + chat support + web.