Hi. I can't find long handed inserters in crafting menu... Somebody knows why?

I'm also seeing that after completing the research "Long Inserter" that I do not get one to craft. It does not appear on the research as a "result" and so may be missing.

Does it perhaps require a factory to make and cannot be made by hand now?

Okay I think I figured it out. Inserters were modified by the inserter overhaul, which is an option you can disable.
If you keep things as they are, you can use Shift+L when you mouse over a normal, placed inserter and it changes to long. You can see more about this in: https://forums.factorio.com/viewtopic.php?t=33826

That's right, also there's a button top left of the screen with a picture of an inserter on it. if you click that a menu opens up where you can choose all newly placed inserters to be long handed.

Bob's Adjustable Inserters mod will give you even more options.