Are you an F-1 student on optional practical training (OPT) with the employment authorization document (EAD) who would like to travel abroad during a pending H-1B cap case? Then it is very important that you be aware of how such travel could affect your H-1B petition, since international travel could result in a denial of your change of status request or even cause you to be barred from entering the US until after October 1st.
If you do not plan on traveling outside the US between April and October 2019 before the H-1B petition is approved, then the petitioner can request a change of status to H-1B and you will not need to depart the US to trigger your H-1B status. You should not depart the US while the petition is pending, since it will cause your change of status request to be abandoned, and then you would have to depart and reenter the US after it is approved and before October 1, 2019, to start working in H-1B status. Also, after the petition is approved, if you depart the US then you must reenter before your EAD expire. Otherwise, you will be barred from reentering the US until the later of October 1, 2019, or the approval of your petition to work in H-1B status.
Your work authorization from your EAD will be automatically extended until October 1, 2019. You will need to have your international student advisor annotate your Form I-20 to reflect this automatic extension. If your petition is not approved by October 1, 2019, then your work authorization will terminate, although you will be allowed to remain in the US. If you do not receive a decision from USCIS by mid-August, then if possible, the case should be converted to premium processing, which requires USCIS to make a decision within 15 days or to request additional evidence.
If you do not obtain an H-1B receipt notice by the time your EAD expires, and you are still waiting to determine if you won a number pursuant to the lottery, then you should be removed from payroll until you get the receipt number.
Please note that you should also check with your international student officer about obtaining an STEM-based extension of your optional practical training. You should file for that extension, unless you have already received an H-1B approval. You can file for the STEM OPT extension while the H-1B is pending.
If you would like to travel in and out of the US between April and October 2019 and your EAD will not expire before the anticipated approval of your H-1B petition, then the petitioner should request that approval start upon your entering in H-1B status after October 1st (or later if the petition is approved later). This will entail obtaining an H-1B visa at a US Consulate abroad (with certain exceptions for Canadian citizens and those taking advantage of automatic revalidation).