We have provided a sample invitation letter for inviting relatives and friends above. You may fill out the highlighted sections using your own information.Get your invitation later and network with experts. Information for international attendees of OTC 2025. Find visa and travel information, tips for navigating the conference, and networking opportunities. Go to "Other Services" and complete the e-form "Invitation Letter Request. Note: We can only provide Invitation letter but not guarantee visa. The invitation letter must be in the English language, so that US officials can read it. We would like to extend to you an invitation to attend. The purpose of this workshop is to provide an opportunity for researchers active in the.