To join multiple polylines into a single polyline, use the PEDIT command with the Multiple and Join options.
* Initiate the PEDIT command:
* Type PEDIT in the command line and press Enter.
* Select Multiple option:
* When prompted to select a polyline, type M for Multiple and press Enter.
* Select all polylines:
* Select all the polylines that need to be joined.
* Use the Join option:
* After selecting the polylines, type J for Join and press Enter.
* AutoCAD will prompt for the fuzz distance. Press Enter to accept the default, which will join the polylines if their endpoints are within a small distance of each other.
* Convert if necessary:
* If the selected objects include lines or arcs that are not polylines, AutoCAD will ask if you want to convert them to polylines. Select Yes to convert and join them.