Motorbikes dont usually come with much luggage capacity as standard. But you can equip most bikes to take all you need for a bit of touring. Though, just like taking a pillion, a bigger machine can carry more with less effect on performance and stability.
A custom-designed hard luggage set offers great security and usually doesnt affect the way your motorcycle rides too much. If you can get the system fitted so much the better. Otherwise, follow the fitting instructions carefully, and check all nuts and bolts for tightness after 200 kms or so.
Be conscious of the possibility of high-speed weave. Some bikes with certain riders aboard can be susceptible when luggage is fitted.
You can also fit plain racks that you can strap luggage to. Some offer an optional top box.
Soft luggage sets are versatile and you can fit them temporarily. Panniers, tailpacks and tank bags come with various mounting systems.
Things to watch out for are weave (though usually not such a problem as with hard luggage) and ensuring nothing dangles or catches.
With soft panniers, make sure nothing can touch the exhaust! Make sure tank bags are not so big that they interfere with your control and ability to shift your bodyweight.