# Custom functions

Custom functions are created by using a Function part to start a series of operations and then ending the series of operations with a Return part.

Each function within the document must have a unique name so that it can be identified when called.

Functions do not have access to variables that are defined in the main flowchart. If a function needs to use variables that are used in a main flowchart, either:

- the variables must be passed to the function as parameters
  or
- the variables must be scene variables.

## See also:

- Built-in functions
- Call function
- Function
- Return