If you are on the deck edit screen:
Clicking the share icon, you can get your public sharing URL.

Then just click the "Copy Link" button to copy your public sharing URL.
If you are on the dashboard/deck list:
Clicking the share icon, you can get your public sharing URL.
Then just click the "Copy Link" button to copy your public sharing URL.
Note: This sharing URL is a public URL, everyone can see your presentation using this public sharing URL.