The Infinity 1 enhancement in Minecraft adds infinity arrows to a bow.
If an arrow is shot at the ground, it should bounce back and can be shot again by switching to a different weapon with right-click or by hitting the Scroll Wheel. If you shoot anything else (A block for example) then its trajectory will not change whatsoever- it will stay on that course until someone shoots another arrow at it, a cave explosion goes near it etc. It does not seem possible to turn off this behavior of shooting arrows and make them automatically come back like they do in vanilla Minecraft without adding mods like TooManyItems which are risky and unstable as we cannot control what other mod might change something in our game without us noticing since something always changes as soon as a mod is added. In any case, even if we could shoot arrows that come back automatically like in vanilla Minecraft, it would be incredibly annoying since it would be totally unbalanced and shooting arrows that come back would definitely give us an unfair advantage over others. The Infinity 1 enhancement in Minecraft makes a bow shoot infinite arrows that will not bounce back.
With the Infinity 1 enhancement, you cannot hold an arrow and fire it again immediately like you can with the vanilla bow. It will disappear if you shoot it at anything except for another player so if you want to shoot another arrow, you have to hold down the Shift key for about a second to switch to another arrow in your inventory.