Click the Search tab on the ArcToolbox window, type a tool name, then click Search to find the tool.

This example shows searching for the Buffer tool.

If you have the Analysis Tools toolbox and the Coverage Tools toolbox added to the ArcToolbox window, you’ll see two Buffer tools in the list of found tools. The Buffer tool in the Coverage Tools toolbox only works with coverages as inputs. The tool in the Analysis Tools toolbox works with feature classes as inputs.

Click the tool and click Locate to see open the toolbox that contains the tool.