You can use the Snap geoprocessing tool to snap together multiple features at their ends, vertices, or edges within a specified tolerance.
This tool is useful for cleaning up features that were not digitized using snapping or were imported from another format, such as CAD. The Snap tool allows you to set up a combination of snapping types, layers, and distances between different layers. For example, you can snap features in the input layer to an edge in one layer and to a vertex in another layer—with different tolerances specified for each case. Some of the scenarios in which you might use this tool include to remove dangling lines, ensure points fall along lines, or match borders that should be shared between two layers.
This tool can operate on only the selected features and also be run inside an edit session.