Gerund is a verbal noun. Since we add -ing to a verb to make gerund, it looks like a present participle.
Gerund can be:
subject of a sentence (Drawing is fun.)
object of a verb (Stop talking!), preposition (Jane is fond of jogging.) or adjective (Is the film worth seeing?)
predicate nominative (His hobby is fishing.)
part of a noun compound (Mark has bought a swimming suit. = a suit for swimming)
Gerunds are also used in short prohibitions (No smoking).
There are a lot of verbs followed by gerunds. You can see a list of these verbs here.
For more visual explanation, watch this video: