Your DS-2019 is a Department of State form that has the following purposes:
The I-94 is the small white card in your passport on which the visa classification and the expiration date of your authorized stay is written when you enter the U.S. All Exchange Visitors should have J-1 written as the visa classification. D/S means the period during which you pursue your stated program plus 30 days in which to depart the country. If you lose your I-94 card you must complete an application form I-102 which can be obtained from UC International Services or the U.S. Citizenship and Immigration Services (USCIS). A fee of $330.00 must be submitted with the application. After details of your entry are verified, a new I-94 will be mailed to you.
A passport is your country’s identification of you as a citizen. Your passport must remain valid at all times. It is not allowed to expire. You may renew it by contacting your Embassy/Consulate within the U.S.
A visa normally is a stamp placed in your passport by an official of the United States (or the country you are entering). A way to differentiate between a passport and a visa is to remember that the passport is your proof of citizenship, while the visa is the other country granting you admission.The date of the visa on the stamped page is only to be renewed if you are going to leave the United States and return after it has been expired. Keep in mind, a visa only admits you to the United States. Having a valid visa does not mean you are in proper immigration status.