An adaptivity process is a succession of analysis jobs where ABAQUS/CAE remeshes selected regions of the model between each job. ABAQUS/CAE modifies the mesh to be used in each analysis job in response to error estimates that were computed during the previous analysis and written to the output database. For more information, see Adaptive remeshing: overview, Section 12.3.1 of the ABAQUS Analysis User's Manual.
You have considerable flexibility in how you execute this succession of jobs. Adaptivity processes are stored in the model database and are maintained between sessions.