There are a range of bags available to carry with you while you ride or transport your bike in. Cycling specific backpacks and shoulder bags are constructed rugged and water resistant materials. They will have padding on the straps or back to improve air flow. Some have waist support to distribute weight evenly.
Panniers are bags that clip or strap onto the front or rear rack of your bike. Pannier bags are great if you plan to carry heavy loads.
Saddlebags are small and neat and attach to the rails of your saddle. They are ideal on long rides and sportives so that you don't need to carry spares and your ride essentials in your back pocket. Saddlebags are available in a range of sizes from ultra compact to big enough to fit pump, tube and multi tool.