## Zoho Billing - Product, solutions, integrations, support, and resources Index

Access the complete documentation index at:
https://www.zoho.com/ae/billing/llms.txt

Use this file to discover all available documentation pages before proceeding.

# Custom Module Preferences

## Approvals

If the records of a custom module has to be approved other users in your organization, you can configure Approvals for the custom module in Zoho Billing. You can choose from **Simple** and **Multi-Level** approval based on your business requirements.

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## Fields & Tables

To fully craft a custom module in Zoho Billing, you can use the form builder to add fields of different data types and tables to the module. Read our help document on the [Basic Functions of a Custom Module](/ae/billing/help/settings/custom-modules/basic-functions.html) to learn more.

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## Preferences

Manage the preferences of a custom module from this tab.

### Custom Modules in Customer Portal

If you want your customers to view and perform actions on the records of a custom module, you can enable the custom module for the customer portal. You can also configure which records they can view and what actions they can perform.

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## Validation Rules

With Validation Rules, you can create rules to set restrictions for the data being recorded.

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## Custom Buttons & Links

Custom Buttons allows you to perform specific actions to purchase orders when the button is clicked. Custom Links opens an external link. You can create them using a deluge script and execute actions based on the functions you add.

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## Related Lists

Related Lists allows you to fetch and view data from within the app as well as from other third-party services. This comes in handy when you want to cross-reference data from different entities.