We were having the same issue today and went digging...here's how to add it if the spashscreen doesn't show up:

In Lacerte, go to Settings --> Options.  Make sure the "Client View" option is on "All Clients", then open the Misc group and find SafeSend.  Select SafeSend, and click > to move it to the "Display" column.  You can move it up/down to rearrange the order from there.

The first time you login, it will ask you to enter your subscription key as well - this article was helpful in hunting that down: https://accountants.intuit.com/support/en-us/help-article/other-articles/finding-subscription-key-sa...

Hope that helps!