Sativa plants are typically taller with long thin leaves. The bud of a sativa plant is typically less dense and somewhat feathery.
Sativa products usually come with a cerebral feeling. This is often referred to as a "head high".
Indica plants are typically shorter with wide leaves. Buds of an indica plant will usually be dense.
Indica products usually come with a bodily feeling. This is often referred to as a "body high".
What is Hybrid?
A hybrid is a cannabis plant that is a crossbreed between an indica and a sativa plant. There are very few cannabis strains that are of true indica or true sativa variety. Instead most strains of cannabis are a hybrid of the two. Within this subset there can be indica dominant, and sativa dominant strains. There are also hybrid strains that are a relatively even indica/sativa split.