The Multi-insert option is located within the table views gear menu, in the edit option.
The idea of a multi-insert is to be able to duplicate SObjects. Here is an example of a multi-insert view.
The most important values that must be entered are the Multiplier, and the Code.
The number entered into the Multiplier box determines how many SObjects that will be created.
Sequence code will determine which sequence the SObjects will be placed under.
The Code value will be incremented by the value that is entered into the Multiplier.
*Note - The value of the Code must start with a letter.
All the other values are optional.