Once you have logged in to your account online, click on the menu icon in the upper left-hand corner. Select Partner Earnings. Here you will see 3 tabs at the top of the page: Payment Statements, Tax Information, Banking. You will automatically be on the Payment Statements tab. Click the Tax Information tab just to the right.
Here, you will be able to click the button to accept an electronic delivery of your 1099 via your email address on file. If you do not select that option, your 1099 will be mailed to your physical address on file. Make sure your physical address is correct. (You can verify that in the Profile page in the menu.)
There is also a FAQ portion on the bottom half of that page to help answer your questions.