Trim installation typically occurs after the drywall is installed. Drywall installation involves hanging large sheets of drywall on the walls and ceilings to create a smooth surface. After the drywall is installed, the seams are taped, mudded, and sanded to create a seamless surface. Once the drywall is finished and ready for further work, trim installation can take place.
Trim, such as baseboards, crown molding, door casings, and window casings, is typically installed after the drywall is complete. Trim installation involves measuring, cutting, and attaching the trim pieces to the walls and around openings. It is important to install the trim after the drywall is finished to ensure that the trim fits properly and covers any gaps or transitions between the drywall and other surfaces.
So, to answer your question, trim is generally installed after the drywall installation and finishing process.