I have mailed my OPT application, when can travel outside of the US?

For student applying for Post-Completion OPT, it is recommended that you wait until you receive your paper Receipt Notice in the mail from USCIS before traveling (within 2-3 weeks of filing).  If you request with your OPT application an electronic (email/text) notification of USCIS receipt of the application (within 1 week of filing), it is possible to travel after receive of that confirmation.

IMPORTANT NOTE: A student can travel outside the U.S. while an OPT application is pending as long as they re-enter the U.S. before their program completion date. A student who would travel outside the U.S. and want to re-enter after their program completion date will require the OPT application to be Approved, have received the Employment Authorization Document (EAD) card, and have a job offer letter in order to return to the U.S. on or after the start date on the EAD card. All of these documents would also be required if the student needed to apply for and obtain a new F-1 visa from the U.S. Consulate abroad in order to re-enter the U.S. 

Please see additional details about Travel after the Completion of Program while on Post-completion OPT on the F-1 Practical Training page of ISO website.