On macOS, Safari can be configured to provide search suggestions "from" a chosen search engine. A similar feature appears to be present in iOS, but it doesn't not work as expected: even when the "Search Engine Suggestions" setting is disabled
search suggestions still appear:
Moreover these suggestions do not come from the search history of the specified engine (e.g., it contains entries absent from the selected engine's history) bug from somewhere else.
Where do the suggestions that appear in the list of suggested searches in iOS Safari come from? How do I remove individual items, or clear them all without erasing other aspects of my browser history or affecting my synced history on macOS?
Best Answer
Those entries appearing as completion suggestions in the mobile Safari drop down under "Google Search" (or your default search engine of choice) are locally cached and are from your personal search history: e.g. somebody on that icloud account had typed "stranger things" in before -- not necessarily on that specific browser.
It can be cleared in the Settings > Safari > Clear History and Browsing Data. This will clear history, cookies, and cached pages (but not bookmarks or passwords) from the browser and from linked iCloud browsers. I tested this, and suggestions disappeared from my Safari "Google Search" list.
Unfortunately there does not appear to be a way to delete cached searches without deleting cached pages.
For a walk through see for example: Cult of Mac: Clear Your Browsing History And Web Data From Mobile Safari -- iOS Tips