when i have dragging a photo into a new document, it may be bigger or smaller in size than new created document and i have to resize the picture via ctrl + t. i seeking for a way or a shortcut to pressing and quickly image fit to document borders. is there any way?
Are you trying to scale the image to the document, or adjust the document to be the size of the image?
Image to Document
When you're transforming the image, grab one of the corners. Hold ALT + SHIFT while you're dragging to scale proportionally from the middle of the image.
Document to Image
The fastest way (that I know of) is to copy the image, open a new document, and under presets there's an option for "Clipboard". Then paste your image into the new document.