Have a look at the SendKeys command in help.

" wrote:

I am attempting to write a macro to automate various testing scenarios
in a neural net program that operates in Excel (Neuralyst V 1.42). I
have nested one of the password protected neural net macros ("NNM1")
in my macro, but NNM1 has an internal "prompt" command that requires
two keyboard entries, in this case two keyboard strokes to the "Enter"
key. What is the VBA command that will give me the two "Enter"
keyboard strokes that the nested NNM1 macro requires?