How to command f search on iPhone

How to do a Command-F search on your iPhone

1. On a webpage, tap the box with the upward arrow on it (at the bottom of the screen)
2. Select the "Find on Page" option (Magnifying glass icon)
3. Type the word or phrase you're looking for
4. Tap the blue "Search" button

Or, as search bar in Safari app is unified :

1. Open website in Safari.
2. Tap on address bar, and type in it a word you wish to find on the website you are viewing.
3. Among search bar suggestions (most likely at the bottom of it) you will see section “On this website” with item ‘Search “<word>”’ on it. Tap on it.