i want 1password to enter the credentials without pressing any button automatic on site load.
Is there a way to get that done at the moment?
That is not something we have ever implemented. 1Password's filling requires intentionality through an explicit command: either selecting the Login item from the extension popup with your mouse or by pressing ⌘\ on your keyboard. If you want something similar you can use 1Click Bookmarks which move the explicit command up the chain a bit. Just open the 1Click Bookmark and you will be logged in (presuming you have already unlocked 1Password; otherwise you will need to enter your master password first).
We never say never, though. I'll pass your vote for this along to the developers. Thank you for your feedback.