Marriage Visa applicants who obtain a green card within two years of their marriage are given conditional permanent residency for a period of two years. At the end of those two years, the conditional permanent resident must apply for the removal of the conditions through an I-751 petition. The process can be completed through an I-751 joint petition (with the U.S. citizen spouse), or through an I-751 waiver petition.
One common concern that I-751 applicants have is that the receipt number on their I-751 receipt notice does not appear on the USCIS’s online status application. This is normal. The solution: When USCIS sends the biometrics appointment notice, check that receipt number on the USCIS website. The biometrics appointment receipt number should appear.
Perhaps USCIS will fix its system in the future, but for right now, this solution will have to do.