When you want to limit the update permissions of a model to certain
groups:

1.  Go to *Settings \> Techinical \> Database Structure \> Models*
2.  Open the form view of the model, and select **Update Restrict
    Model**
3.  Assign the groups that should be exempt from the restriction to
    **Update-allowed Groups**

When you want revoke update permissions for a specific user:

1.  Go to *Settings \> Users & Companies \> Users*
2.  Open the user's form view and click the **Read-only** smart button
3.  In case you wish to exclude some models from being read-only, go to
    *Settings \> General Settings* and update **Excluded Models from
    Read-only** under the Permissions section by listing the models
    separated by commas (e.g., sale.order,sale.order.line).