# Rules

**Introduction**

Rules can be created based on repository metadata. For example, this is a rule that applies when the value of the contract is greater than $10,000:

 

![](https://support.aerofiler.com/hc/article_attachments/360089149714/mceclip0.png)

Here is a more complex rule that applies when the contract is greater than $10,000 and the Region is "Rest of the World":

 

![](https://support.aerofiler.com/hc/article_attachments/360091300113/mceclip1.png)

**Application**

Rules are used in approval workflows in two contexts:

1. A rule can determine whether a particular document should be reviewed at a particular step. For example, you may have a rule that Finance only reviews contracts above a certain dollar threshold.
2. A rule can determine whether a particular field should be displayed. For example, if sales tax only applies in a particular region, you can configure Aerofiler to only display the sales tax field if the region matches.