In a scenario step, you can parameterize a value. Notice that the you can change the value of a parameter without affecting the default value. It makes the step more flexible and easy to reuse.

Create parameter in a scenario step.

Click on link icon to open step definition detail (or select step from Step Definition section on meny sidebar)

When step definition window is opened, click on the scenario name and input syntax: “parameter”. The parameter will be add in Parameters section. 

User parameter with scenario outline

After create parameter, back to scenario details, click on the empty field and input syntax <name_of_header> e.g: <header>

For creating and using scenario outline, refer to this link

User parater with environment variable

After create parameter, back to scenario details, click on the empty field and input syntax =${name_of_variable} e.g: =${username}

For creating and using environment variable, refer to this link

Use parameter in automation command

In input value dialog, select value type = variable (notice that some command don’t have input value). Then you can choose the parameter that created.