can i enter on F1 visa while H1 application is pending?

The difficulty is that any travel outside the United States during the time that an H-1B petition is pending is considered an abandonment of the change of status portion of the petition. With your OPT EAD valid until January 2019, you can travel with the above restriction. You might be better off waiting until the H-1B petition is approved before traveling under your OPT EAD before October. Then it might be considered that you did not travel during the time that the H-1B petition was pending. If the change of status portion of your H-1B is not considered abandoned and you did request the change of status, you would not be required to have an H1B visa in your passport in order for you to begin work in October or later when the H-1B petition is approved. Please note that I along with most of the lawyers will discourage applicants even with EAD’s to travel at any time before an H-1B becomes effective in October or thereafter. Due to the limitations of the Lawyers.com Forums, Alan Lee, Esq.'s (the "Firm") participation in responding to questions posted herein does not constitute legal advice, nor legal representation of the person or entity posting a question. No Attorney/Client relationship is or shall be construed to be created hereby. The information provided herein by the Firm is general, and requires that the poster obtain specific legal advice from an attorney. The poster shall not rely upon the information provided herein as legal advice nor as the basis for making any decisions of legal consequence.