What is in the managed Sheet, and what you can change
A Webtzm-managed spreadsheet has one working tab, and optionally a second read-only one.
The delivery tab is the real record. Column A is webtzm_id, the record ID an Update or Delete uses to find the right row again. Webtzm writes it and protects it from edits, so the row stays findable. Your fields follow, then the delivery timestamps.
The clean view is an optional second tab holding only the columns you choose. It is a live formula over the delivery tab, not a copy, so it updates by itself and can never disagree with the record. That also makes it read-only: edit the delivery tab, never the clean view.
If you change the Sheet
| If you | What happens | How to recover |
|---|---|---|
| Rename a column header | The next delivery treats it as a new column and adds the original name back beside it. | Rename it to the original spelling, then move the values across yourself. |
Move webtzm_id out of column A | Update and Delete can no longer find rows. | Move it back to column A. |
| Delete a reserved column | Delivery adds it back on the next submission. | Nothing to do. Hide it instead of deleting it. |
| Rename the delivery tab | Delivery keeps working, because it is addressed by tab id rather than by name. The clean view breaks, because its formula names the tab. | Re-create the clean view from the workflow. It is rewritten against the current tab name. |
| Rename or delete the clean view tab | Nothing is lost. It holds no data of its own. | Re-create it from the workflow. |
Renaming the delivery tab is the one that surprises people: everything still arrives, and only the tidy second tab fills with errors. The delivery tab is always the authoritative one.
What an Update writes, and what it leaves alone Pro
An update changes only the answers it receives filled in. A field the visitor leaves blank keeps whatever the row already holds, so one update cannot quietly empty the columns it did not ask about.
That also means a blank cannot empty a cell on purpose — a blank box and an unasked question look identical. To empty one, your own code sends null for that field. A published form cannot send it, so only an integration you control can clear a stored answer, and the cell is emptied for good when it does.
Use a Sheet you already have
Everything above describes the Sheet Webtzm creates for you, which is the default. When you would rather deliver into a spreadsheet you already own, choose Choose an existing Sheet in the workflow's output setup and pick it from the Google Picker that opens — the same file-picker dialog Google shows anywhere it lets you choose a file from your Drive.
Picking a Sheet grants Webtzm access to that one file, nothing else in your Drive. If Webtzm says it cannot open a Sheet you named by pasting a link instead of picking it, open the picker and choose it there — that is what grants the access a pasted link does not.