# Defining matrix parameters

Business data from application documents is sent to workflow as workflow input parameters. Workflow parameters are mapped to matrix parameters when a matrix is evaluated. The conditions that can be used for a parameter are specific to its data type.

Matrix parameters can be added or edited only when the matrix is created and not approved. After a matrix is activated, its interface, which is composed by the matrix name and its parameters, cannot be changed anymore.

Each parameter that is defined here must be used in one of these ways:

- As a column name or as a comparison parameter in a matrix condition.
- For an approval matrix, as a distribution option for “distribute to value from parameter”.
- For a decision matrix, as a parameter to be set.

You can only remove parameters that are not used in the matrix definition. To remove a parameter that is used, first remove the matrix column or rows where this parameter is used.

To define the matrix parameters