Needles used for sewing machines differ from those for hand sewing. On a machine needle, the hole is at the bottom instead of the top, and the base of the needle has a flat end to be inserted into the machine and fastened tightly with the screw tab.
An generalist needle with no special features. Can sew most fabrics. Check the thickness of the needle for the weight of your fabric.
Unlike other needles, a ballpoint needle has a purposely rounded tip. This is because the needle is intended for stretch knit fabrics, and the dull tip allows it to pierce those fabrics without snagging or pulling. If you are trying to sew woven fabrics and there is a ballpoint needle in the machine, simply replace it with a universal needle and put the ballpoint back. Do not throw these needles into the trash unless they are bent. They are supposed to be rounded and dull.
Similar to the ballpoint, intended for fabrics with a high amount of give to prevent skipping and snagging.
A needle with a thicker shaft and sharper point to help penetrate thick, dense layers of denim. Thinner needles will bend or break under the strain and are not recommended.
Thinner and more delicate that the average needle, for very fine fabrics like organza or chiffon. This needle won't punch visible holes in expensive delicate fabrics.
Similar thickness to a denim needle, this needle also has a sharp triangular blade for a tip, designed for punching through non-woven fabrics like leather and polyvinyl.
A needle with a cut in the threading hole designed to be easier to thread. You will never need this.