# Entering Expressions in an EHR

When enabling postcoordination in an EHR, it is important to be aware of how the approach selected for entry of the expression impacts the storage and the display of the expression.

There are three main approaches to entering postcoordinated clinical data into an electronic health record.

* [Prepopulated expressions](https://docs.snomed.org/snomed-ct-practical-guides/snomed-ct-postcoordination-guide/expressions-in-the-ehr/entering-expressions-in-an-ehr/prepopulated-expressions)
* [Form-based selection of expression parts](https://docs.snomed.org/snomed-ct-practical-guides/snomed-ct-postcoordination-guide/expressions-in-the-ehr/entering-expressions-in-an-ehr/form-based-entry-of-expressions)
* [Free text with Natural Language processing to encode the free text with SNOMED CT](https://docs.snomed.org/snomed-ct-practical-guides/snomed-ct-postcoordination-guide/expressions-in-the-ehr/entering-expressions-in-an-ehr/free-text-with-natural-language-processing)

The following pages will elaborate on each of these approaches and clarify key requirements for each. Furthermore, best practice approaches to the storage and display of expressions will also be presented.

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