You can edit an item of a data list if you have editor permissions or higher in the application you are working in.

To edit an existing item, find the item you want to edit in the data list, and click on the item to open its details page.

You can find the blue "Edit item" button from the top-right of the detail page.

Click this button to open the item's editing page.

By default, the editing page will show as a pop-up window with default layout. You can change the form layout by adding a custom list form, and set it as the edit item form.

You can also change size of the pop-up window from small, medium, large or full screen. Or, you can change to open editing page as a new full page.

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