Now I understand what is fader head, but where is an option key I have to hold down? How it looks like?

The Option key at the bottom of your keyboard, on either side of the Spacebar..

Yes, I see, but I have there not option written, but alt and a symbol. But it's still the same.. ?

Yes, Alt is the same as Option.

You say that a recording level is a level of the incoming signal. From where the incoming signal comes? Is it only outer one ( a voice, real instruments)? What I hear on my project, if the recording level is low, or if it is high? If I change a recording level, what is changing on the project? I understand, if I change a volume, then I hear a difference. What difference I hear, if I change a recording level? Thanks!

Yes, the recording level is the level of the incoming external signal (like a real guitar or vocal/microphone). This sets the level of the recorded audio file -- it should be loud enough to display the waveform clearly, but not so loud that the incoming signal ever clips (lights up the red overload button(s) for that channel). Once the signal is recorded at that level, then of course you can change the playback level at any time with the volume slider in the track header.

I opened the gb and tried to try the recording level. If I chosed from track list already recorded bright vocal, on the left of piano roll I saw it and there were two choices - track and region. There were not master choice between track and region, as on your screenshot here. Well, I chosed a track, but I didn't get recording level as you. I got a pitch correction with two choices below - limit to key and enable flex. And it has also a slider I can move from beginning to the end. Is it a recording level by other words, or what is a pitch correction? If not, where are my recording level and how can I use that pitch correction?

If you're seeing pitch correction options then you're in the wrong panel -- you're looking at the Edit panel (shortcut "E"), but you need to be in the Smart Controls panel (shortcut "B") to access the Recording Settings.

Yes, you are right. Now I see recording settings, there is a recording level, and there is an option automatic level control (like on your screenshot). It's not chosen here. If I already have an automatic level control and can activate it, then why I need to move a slider by myself.. ?

Automatic level control will limit or compress the incoming signal and may have an adverse effect on sound quality -- professionals prefer to set the recording level by hand.