Common to: eeSchema and PCBnew
In both:
The pointer button, at the top of the right hand tool bar, selects a mode in which it is easy to pick up, move, drag, edit the objects on the drawing.
It is a tool you will use much of the time.
If you are in a different tool, sometimes pressing the "escape" key once, sometimes twice, will switch you back to having the pointer button selected. It is easy to make this change of selection inadvertently.
In PCBnew:
In PCBnew, the "Mode footprint: Manual and automatic…" button near the right hand end of the top toolbar has an effect on what you can do when the Pointer button is selected.
That label, "Mode footprint…" makes more sense to me if I re-do it as "Mode: Footprint (Manual or automatic…)".
Each setting has it's uses. One big effect is that with the "Mode Footprint" button "down", you cannot pick up the "Reference" and "Value" fields associated with a given component… any attempt to pick something up gives you the whole footprint, fields and all. Excellent for general work. You can also use the "Glob(al) move and place" tool when the "Mode Footprint" button is down. (Right click on "page" to access it.)
For fine tuning of your artwork, in particular the positioning of "Reference" and "Value" fields, you still use the pointer tool… but you have to be sure that the "Mode Footprint" button is "up".
(This entry may need revising. If you particularly want THIS expanded, write and cite "Page bu1point")