Yup.
http://help.machform.com/m/using-machform/l/560179-using-url-parameters-to-populate-form-fields
You'll have to find the element ID for the field you want to populate. Would be nice if Machform allowed us to name each field, so the parameters can be something like "?email=123@456.com" rather than "?element_1=123@456.com" but at this stage it does not (afaik).