I mean this text "Please note that you may have permissions to edit content in the frontend, but you do not have publishing rights.
The admin of this site will approve your item after moderation."

and is it possible to change logo K2 in this form?

You can change the text by editing the correct phrase in one of K2's language files.

Yes you can change the K2 Logo in this form. Simply locate the source of this image with your browser and replace it with a custom image of yours.

@Matt
Glad to see you participating - it may be rewarding for you
and others as well

thank you for answer, you really helped me :)