Question

How would you select the required portion of the text in a document?

Answer 1

A comprehensive answer to your question regarding the selection of a required portion of the text in a document will comprise of some options to smartly select:

Click Mouse Right Button and drag
It is the most common way of selecting any portion of a document by right-clicking and dragging the cursor over the required part.

[Shift]+ any arrow key
From your current cursor position, keep [Shift] pressed and press any arrow key to select a specific character or a line or part of a line.

Triple Click
Selects the current paragraph

[CTRL] + A
It selects the entire text of the document

[Shift] + [Home] or [Shift] + [End] 
Pressing [Shift] + [Home] selects everything from the insertion point to the left margin in the current line. Similarly, [Shift]+[End] selects everything from the insert point to the last character to the right.