Reaction arrow types

Press W for the Arrow tool. The row above the toolbar shows every arrow; press its number to pick it, then drag on the canvas.

The arrows

Key	Arrow	Means
1	forward	The reaction goes from left to right
2	equilibrium	A reversible reaction, at equilibrium
3	lies forward	An equilibrium that favors the products
4	lies backward	An equilibrium that favors the starting materials
5	resonance	Two drawings of the same molecule, not a reaction
6	retro	Retrosynthesis: the target on the left is made from what is on the right
7	curly	A pair of electrons moving, in a mechanism
8	fishhook	A single electron moving, in a radical mechanism
9	no reaction	The reaction does not happen under these conditions
	dashed	A step that is implied, or several steps in one
	plain	A line with no meaning of its own, for layout

The picture shows each arrow once, top to bottom, in the order of the table.

Curly and fishhook arrows bend: drag from where the electrons start to where they go. See How to draw curved arrows for a mechanism.