Impedance measurements are performed using a  tympanometer and the results are imported into Audiqueen (see this support page for details).

The button Manual Input is always disabled for the Impedance test type, even if the Manual Input Only checkbox is checked in the Format window.

The reason for this is that it is virtually impossible to manually enter all the points that constitute a tympanogram or reflexes.  Audiqueen does not support drawing these lines manually.

How then can I enter tympanograms with or without stapedial reflexes as a pdf report?

If you want to import pdf files of impedance measurements, this can be done by creating a Custom Test (see the support pages for details).  In that case, the tympanometer generates the pdf file, or it generates a printed result that you scan into a pdf file.

The custom test can be named Impedance Doc, for instance, and you can use the following icon, or any icon of your choice, to attach to it.

The icon then appears in the ribbon at the place that you defined, and the Manual Input is enabled.  You can also set Audiqueen's Easy File Fetcher as software to collect the pdf's automatically.  In that case, the Measure Now button will also be enabled.

This feature is not available in the web viewer.  
Audiqueen's web viewer displays the impedance documents entered in Audiqueen's Workstations.