---
schema_version: "1"
id: 10f8d3f2bcee4d8ecf52b9a982d678f462e2c9e9a8ed3f343a1371c697703db5
title: Import File Guidelines
collection: admin
version: current
locale: en-us
portal_url: https://docs.salesforce.com/admin/current/en-us/mktg/264-0-0/mc_moc_prepare_file_for_import.md
canonical_url: https://help.salesforce.com/s/articleView?id=mktg.mc_moc_prepare_file_for_import.htm&release=264.0.0&type=5
source_site: help.salesforce.com
content_type: documentation
content_hash: 539c8e77bdec40edcab828abc01f2a0ce9a46ffc08c28c7bdfc6467a6793ce02
description: Follow these guidelines to prepare your contact import file. The import file must be in a comma-delimited (.csv) format, 20 MB or less.
products:
  - Marketing
  - Marketing Cloud Engagement
release: "264"
---
# Import File Guidelines

Follow these guidelines to prepare your contact import file. The import file must be in a comma-delimited (.csv) format, 20 MB or less.

Each column header is a default demographic field or custom attribute. Use these guidelines to format each header.

- Start with an underscore ( \_ ), followed by the field name in title case.
- Remove any spaces in or around the header.
- Include required fields \_MobileNumber, \_Locale, and \_ContactKey.

Each row is a unique contact. Use these guidelines to format the values for each contact:

- For mobile numbers, include numeric locale codes and area codes.
    
    ![Note](https://sf-zdocs-cdn-prod.zoominsoftware.com/tdta-mktg-mc_mobile_studio-264-0-0-production-enus/26e7f9fa-f44c-489b-9b21-135d26904a29/images/icon_note.png)
    
    Note This locale code applies only to the mobile number itself. Any other field containing locale information must conform to [ISO-3316-1 alpha-2 standards](https://www.iso.org/iso-3166-country-codes.html).
- For mobile numbers and contact keys, remove special characters such as plus signs (+), hyphens (-), or parentheses.
- To use timezone-based message sends, add \_UTCOffset and \_IsHonorDST values.
- To import a contact as opted out for a short code or specific keyword, add a \_Status column with a value of Unsubscribe.

#### See Also

- [MobileConnect Demographics Table](https://help.salesforce.com/s/articleView?id=mktg.mc_moc_demographics_table.htm&release=264.0.0&type=5 "Descriptions of the fields of the demographics table in MobileConnect.")