Why there is no password, why the address stays private, and what the form does and does not record.
The form has no login. That is a decision, recorded when the app was set up, not an oversight: it is a small internal tool for a couple of people, and a login was judged more protection than it needs.
The flip side is that anyone who has the web address can submit. Nothing else stands in the way — no password, no approval step, no limit on how many rows a stranger could add. The address is the only protection there is.
(The page also tells search engines not to index it, so it will not turn up in search results — but that is a request, not a lock, and it does not change the advice above.)
The Submitted By name is picked from a droplist by whoever is filling in the form. The server refuses any value that is not on the list, so the column can only ever hold one of the known names — but nothing verifies that the person picking a name really is that person. Read it as who says they wrote this, a convenience label for telling entries apart. Never treat it as evidence, and never base an approval or a permission on it.
A submission stores exactly four things, all visible in the shared spreadsheet: the spec type, the description you typed, the name you picked, and the time the row was saved. Everyone who can open the spreadsheet can see every row, so write descriptions accordingly.
Nothing else about you is stored by the app. The choices it “remembers” — your usual spec type, your name, your site — live only in the browser on your own device, never on the server. Clearing that browser’s site data simply makes the form forget them; you pick them again next time, and nothing in the spreadsheet changes.