How to set up autocomplete in Google Chrome?

Question

Google Chrome

Good afternoon. Can you please explain how autocomplete fields work in Google Chrome? Why in this box

<input type="text" name="1419266025" value="" size="20" class="fields string">

I enter something, let's say "Hi". I press "save". And the next time I enter the letter "P" in this field, I get "Hello"
The opposite situation with the same field, in a similar system, but a little twisted, on another server:

<input type="text" name="1476257784" value="" size="20" class="fields string">

So that I do not enter, that I do not save, auto-complete in any