Majorana fermions are promising candidates for storing and processing information in topological quantum computation. The ability to control such individual information carriers in trapped ultracold atomic Fermi gases is a novel theme in quantum information science. However, fermionic atoms are neutral and thus are difficult to manipulate. Here, we theoretically investigate the control of emergent Majorana fermions in one-dimensional spin-orbit-coupled atomic Fermi gases. We discuss (i) how to move Majorana fermions by increasing or decreasing an effective Zeeman field, which acts like a solid-state control voltage gate, and (ii) how to create a pair of Majorana fermions by adding a magnetic impurity potential. We discuss the experimental realization of our control scheme in an ultracold Fermi gas of 40K atoms.