Around an isolated positive point charge, conventional electric field lines point radially outward.
Electric field direction is defined as the direction a small positive test charge would be pushed. A positive source charge therefore has field lines extending away from it, while an isolated negative charge has lines directed toward it. The lines are a visualization rather than physical threads in space.
Field-line diagrams also communicate strength: where lines are drawn more densely, the field is stronger. For a point charge in empty space, field strength decreases with the square of distance. Field lines never cross, because the electric field at any single point has one definite direction.
The word “conventional” matters because electron motion can be opposite to conventional current and to the force direction experienced by a positive test charge. Field lines begin on positive charge and end on negative charge, or extend to infinity when no opposite charge is present.