When exporting entries, only the fields configured in the View will be shown. If a user can not see a field by accessing the View, they will not be able to access it by CSV export.
View Settings: Allow Export: Exporting entries as CSV or TSV from GravityView
In View Settings, click on the tab named "Permissions" and check the box named "Allow Export"
To export all entries in a View (not just one page), check the "Show all in CSV" checkbox
Update the View

Go to the View

To export the View as CSV, add "/csv/" to the end of the URL
The URL before: http://the-cupola.dev/view/guest-list/
The URL after: http://the-cupola.dev/view/guest-list/ csv/
To export the View as TSV, add "/tsv/" to the end of the URL
The URL before: http://the-cupola.dev/view/guest-list/
The URL after: http://the-cupola.dev/view/guest-list/ tsv/
When accessed, a file will be downloaded with the entries

The file's name will be the name of the View by default. Developers can modify the file name by
using this code.
Click "Add Widget" in the Multiple Entries Layout tab then click the widget named "Custom Content"
Click the gear icon to edit the Custom Content widget settings
<a href="http://the-cupola.dev/view/guest-list/csv/">Download as CSV</a>
We checked the box to "Automatically add paragraphs to content" to give the link more space.
Save the View

Now the link appears in the View. Clicking it will download the entries as CSV.

If the page shows Error 404 when trying to download a CSV file
- Go to your site's Dashboard
- Click on the Settings menu
- Click on the "Permalinks" link in the Settings menu
- Do not make any changes, just click the "Save Changes" button