Nuclear magnetic resonance (NMR) is one of the most powerful methods for determining the structure of chemical compounds. Its importance in organic chemistry is enormous, while in the study of solids the role of NMR is less due to broadening of NMR signals. Despite this, the solid-state NMR allows to obtain a lot of information about the physical processes occurring in a substance. An example of such a field, in which solid-state NMR plays a major role, is superconductivity (SC). Lanthanum superhydride is a SC polyhydride with the highest critical temperature (TС ≈ 250 K) among known compounds. For this reason, the La-H system is one of the most attractive objects for solid-state NMR research. In this work, the formation of La polyhydrides was studied in diamond anvil cells at pressures up to 165 GPa in a temperature range from 5 to 300 K. To detect nuclear induction signals from the hydrogen spin-system in our micro samples (d ≈ 30 μm, t ≈ 5 μm), we used a system of Lenz lenses sputtered on diamond anvils. La metal and LaH3 were used as a starting material, while ammonia borane complex (NH3BH3, AB) served as a hydrogen source. In my talk, I will pay special attention to calibration experiments, detection of the hydrogen background signal, and comparative 1H NMR studies of cerium (TC ≈ 80 K in 7 T field) and lanthanum (TC ≈ 230 K in 7 T field) superhydrides.