The Belle and Belle II experiments have collected a 1.5 ab$^{-1}$ sample of $e^+e^-$ collision data at centre-of-mass energies near the $\Upsilon(nS)$ resonances.
These samples contain a large number of $e^+e^-\to c\bar{c}$ events that produce charmed mesons and baryons.
We present searches for rare flavour-changing neutral current $c\to u \ell^+\ell^-$ processes in several decay modes.
Further, we study several decays of the $\Lambda_c$ and $\Xi_c$
to determine branching fractions, as well as $CP$ asymmetries in singly Cabibbo-suppressed decays.

