Goto moves a program to the given label. If the label does not exist, that causes an error.
:Goto WB : : :Lbl WB
In the above example, the program would branch from Goto WB and move to Lbl WB. The WB on the Goto and Lbl tells the program what label to goto.
TI-Basic_Z80_Programming/List_of_Commands/Lbl for information on acceptable label names and usage of this and the label command.