# Defining a Model

## From an Existing Model

Chances are, there is already a model that at least partly fits your needs.

Click on Catalog to check the prebuilt models, and when clicking on one of them, you'll be able to create a copy to "My Models".

You now have a model with a **prebuilt** data schema that you can modify, using the "Data Schema" tab as explained in more detail in [#modifying-your-data-schema](https://docs.mindee.com/models/models-overview#modifying-your-data-schema "mention").

For instance, here is a demo of how to create a model from the Invoice Pre-built model: 

{% @supademo/embed demoId="cmieehzyjar67b7b4lf5tgvrb" url="<https://app.supademo.com/demo/cmieehzyjar67b7b4lf5tgvrb>" %}

## From Scratch

If you don't find something that matches your needs in the catalog, you also have the possibility to click on **Create Custom Model.**\
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You'll have two possibilities :

* upload a sample document&#x20;
* write the document type&#x20;

Our AI Agent will then create a custom model for you.\
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You now have a model with a **custom** schema that you can modify, using the "Data Schema" tab as explained in more detail in [#modifying-your-data-schema](https://docs.mindee.com/models/models-overview#modifying-your-data-schema "mention").\
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Here is a tutorial that shows how to create a custom model by filling in the document type and by uploading a sample doc.

{% @supademo/embed demoId="cmiem2hsob2x5b7b4ye1il6a8" url="<https://app.supademo.com/demo/cmiem2hsob2x5b7b4ye1il6a8>" %}