WFA is currently not equipped with an option to provide checkboxes but we will be addressing this in our upcoming releases but for the time being i can suggest a solution:
1.Create a user input :$WantArchiveLog [Accepting true or false] in the advanced tab of 'Create volume' command of the workflow.
2.Now, choose the condition:
'If the following expression is true'
Hence the 'create volume' command will execute only if the user wants it as specified in the input.
In the preview/execute operation, $WantArchiveLog user input is asked and the command will execute based on this input.
Hope this works for you. Please get back to us in case of further queries.
It would be helpful if you can pass the workflow so that we will be able to help you better.