You can save your custom tools so you can reuse them in
other GeoGebra constructions. In the Tools menu, select Manage Tools. Then, select the custom tool you want to save
from the appearing list. Click on button Save
As… in order to save your custom tool on your computer.
Note: User defined tools are saved as files with the file name extension GGT so you can distinguish custom tool files from usual GeoGebra files (GGB).