After receiving the US F1 visa and collecting my passport, I got a yellow slip. What does that mean?

Receiving a yellow slip means that your visa has been checked. You will know whether it has been approved or not in a few days.

The U.S. F1 visa is issued to students studying full-time in the United States. There is no quota limit. F1 visa holders can work on campus. If you want to work off campus, special approval is required; F2 visa is issued to international students (F1 visa Holder) spouse, children.

If you have received an admission letter from a U.S. school, you can apply for an F1 non-immigrant visa from the U.S. embassy or consulate overseas or the Immigration Bureau. However, these schools must be recognized by the US Citizenship and Immigration Service and qualified to recruit foreign students.