If two of more line features are selected, the Insert Vertices and/or Split at Intersections of Selected Features option will appear when right-clicking. Selecting this option will find all intersections between selected line features and allow you to insert new vertices in the selected lines at the intersection locations if there are not already vertices at the intersection and or split the lines at any intersection or only existing at-vertex intersections.
This is a very powerful command allowing you to make a line network have node-to-node connectivity and even make sure that lines terminate at intersections if required for your application. This is commonly used for making routable street maps.