The ellipsis mark is also called a "suspension point" or "dot dot dot".
The ellipsis mark consists of three dots (periods). We use the ellipsis mark in place of missing words. If we intentionally omit one or more words from an original text, we replace them with an ellipsis mark.
We sometimes also use an ellipsis mark to indicate a pause when someone is speaking, or an unfinished sentence. Look at these examples:
Do we use a space with an ellipsis mark? That is a question of style. Many style manuals recommend no space, like this:
Others recommend using a space before and after an ellipsis mark, like this:
The important thing is that you choose one style and use it consistently. Do not mix your styles.