USCIS announced it received approximately 233,000 H-1B petitions during the filing period, which began April 1, including petitions filed for the advanced degree exemption.
On April 13, USCIS used a computer-generated random selection process, or lottery, to select enough petitions to meet the 65,000 general-category cap and the 20,000 cap under the advanced degree exemption. The agency conducted the selection process for the advanced degree exemption first. All unselected advanced degree petitions then became part of the random selection process for the 65,000 limit.
We can expect email receipts for premium processing cases to start being issued in the upcoming days however USCIS announced that the 15 day premium processing period will start on April 27 regardless of the date on the I-797. For normal processing cases, the receipt notices should start being issued in the next two weeks via regular mail. Once all receipts are issued for cases selected in the lottery, then cases not selected in the lottery will be rejected and returned with their filing fees.
Source: USCIS Completes the H-1B Cap Random Selection Process for FY 2016; H-1B Cap Premium Processing to Begin April 27