You can export fields in a Table to a CSV file or Excel file. You can also import data from a CSV file or Excel file to fields in a Table.
For the detailed steps, refer to the following page.
Exporting Data to a File
Importing Record Data from a File into an App

Please note the following points when you export or import records including a Table to and from a file.

• To import data from a file to an app, the "Import from file" permission must be granted in the Permissions for App settings. Similarly, to export data to a file, the "Export to file" permission must be granted.
  By default, the "Export to file" and "Import from file" permissions are granted only to app creators.
  Reference: Configuring Permissions for Apps

• If the table has Attachment fields, you cannot perform bulk update.
  If you are to add new records in bulk, you can import data into the fields in the table except for the "Attachment" field in the table.

• If a table contains a "Lookup" field and the Prohibit duplicate values option is disabled for the field that is specified as Key Field in the setting of the "Lookup" field, you cannot bulk update data in the table.
  If you are to add new records in bulk, you can import data into the fields in the table except for the "Lookup" field in the table.

• If a table contains a "Lookup" field and settings are configured as described below, you cannot bulk add/update data in the table.

  • A user who carries out the Import from File operation is not granted the "View records" permission in the app that is specified as Datasource App in the setting of the "Lookup" field.
  • A user who carries out the Import from File operation is not granted the "View" permission for the field that is set as Key Field in the "Lookup" field setting.