Despite wonderful achievements during the past decades, the origin of trans-iron elements is not yet fully understood. Trans-iron elements are mainly produced by the slow (s) and rapid (r) neutron-capture processes. Beside the s- and r-process, several other secondary processes were identified and are probably necessary to account for the diversity of observations. These include the intermediate neutron capture process (i-process), occurring at neutron densities intermediate between the s- and r-processes and the p-process, which provides a possible explanation to the production of the stable neutron-deficient nuclides that are observed in the Solar System. The astrophysical sites for the i- and p-process are widely debated. In this presentation, I will focus on the s-, i- and p-processes in (rotating) massive stars and in asymptotic giant branch (AGB) stars. I will review how these processes work, highlight their chemical fingerprints, identify key reaction rates and compare model predictions with the chemical composition of observed stars.
