It's not always easy to interpret NMR spectra. Different nuclei can show the same chemical shift, leading to overlapping signals. NMR signals are also not infinitely sharp, overlapping signals are rather common.
But there are also more advanced experiments you can use to solve these issues, if you have enough of your sample and enough time on a spectrometer.
1H NMR is the most common type because 1H is almost 100% abundant, and hydrogens are present in most organic compounds. 13C and 15N are also used often because they are common in organic chemistry and especially in biology. Those isotopes are rather rare in nature though, this makes experiments involving them much, much less sensitive than proton NMR. If you want to perform more complicated experiments with these nuclei you have to isotope-label your sample, which is routinely done for proteins, but extremely expensive or even impossible for small organic molecules.
19F is another isotope that works well for NMR, it is also around 100% abundant and therefore very sensitive.
In general, you can do NMR on any spin 1/2 nucleus. Nuclei with higher spins is also possible, but that gets more difficult.