Section through a wire: electric flow convention
Looking at the cross section of a wire you see:
But scientists needed a convention to show which direction electrical current flows through the wire.
They did so using the mnemonic of an arrow.
Scientists said an arrow coming towards you would look like this:
And they said that an arrow fired away from you would look like this:
This same convention works for the current direction in wires.
The convention would be that the section through the wire is as follows:
Now, with the battery turned around . . .
. . . the current flow going away from you would have the convention: