How the list builds itself without asking.
Autofill is not a single saved profile you set up deliberately, it is a running list a browser assembles from every form you fill in, one entry at a time. Type a name into one field, an address into another, and the browser offers to remember them for next time, often through a small prompt easy to accept without reading closely. Over months this becomes a fairly complete record of names, addresses, phone numbers and email addresses typed anywhere on the device.
The list rarely gets reviewed because nothing prompts a review. A password manager sends the occasional reminder about a weak or reused password; the plain autofill list for addresses and names has no equivalent nudge, so it simply grows in the background for as long as the browser is used, unnoticed until something surfaces it unexpectedly.
What it looks like from someone else's side.
The risk is not that autofill sends this data anywhere, it stays local to the browser, the risk is what it offers to suggest to whoever is typing next on that device. Start typing an address into a form and a dropdown of previous entries appears beneath it, visible to anyone standing close enough to glance at the screen, which matters more on a shared or family device than a personal one used only by you.
A single character can be enough to trigger it. Typing just the first letter of a street name can surface a full previous address in the dropdown, which is efficient when you are the one typing and slightly alarming when someone else is watching over your shoulder as it appears.
Reviewing what has been saved.
Chrome keeps the list under Settings, Autofill and Passwords, Addresses and More. Safari keeps it under Preferences, then AutoFill, with separate toggles for contact information, credit cards and other forms. Firefox keeps it under Settings, Privacy and Security, Forms and Autofill. Each shows the actual saved entries individually, not just a toggle, so it is worth opening the list at least once to see exactly what has accumulated rather than assuming it is empty.
A sensible middle ground.
Turning autofill off entirely is one option, though most people find retyping an address every single time more friction than they want. A middle ground works better for most: keep autofill on for routine things like a home address used for deliveries, and delete individual entries tied to anything more specific, a hotel address typed once while arranging an evening as overnight, for instance, rather than switching the whole feature off.
A quick way to judge whether an entry is worth keeping is to ask whether it would be fine for it to appear as a suggestion in front of anyone else who ever uses the device. Anything that fails that test is worth deleting immediately rather than left for a later, more thorough cleanup that may not happen for months.
Doing the same review on a phone.
Mobile keyboards add a second autofill layer on top of the browser's own, since the phone's system keyboard can learn and suggest entered text independently of whichever app is being used. On an iPhone this sits under Settings, General, Keyboard; on Android it sits under the keyboard app's own settings, usually reached through the phone's main Settings menu under Language and Input. Clearing the browser's autofill list alone leaves this second, keyboard level list untouched, so a full review covers both.
A password manager, if one is used, keeps a third list entirely separate again, storing not just passwords but often addresses and payment details too, depending on which manager is installed. Reviewing all three, browser autofill, keyboard suggestions and password manager entries, once in the same sitting rather than assuming clearing one clears the others, is the only way to be confident nothing has been missed.
Where this connects to the rest of your habits.
This sits close to the ground covered in clearing browser history properly, since a full data clear removes saved form entries along with everything else, and close to browser profiles too, since a separate profile used only for personal browsing keeps its own autofill list entirely apart from a work profile's. Neither of those guides replaces the simple habit of opening the autofill list occasionally and deleting what no longer needs to be there.
None of this changes how quickly our companions filed under slim or curvy can be reached, or how rates are confirmed for a companion based around Amsterdam West. It only changes what your own browser quietly holds onto afterwards, and reviewing it once tends to be enough to keep the list reasonable for months afterwards rather than something needing constant attention.