Excel stores data in a flat, spreadsheet structure without enforcing contact-specific formats. Phone numbers, leading zeros, and international codes can be auto-formatted or truncated, and special characters may be misread. Names or addresses split across columns may not map correctly in mobile contact apps, causing errors or formatting loss. To prevent this, data should be converted into a structured contact format like vCard, which supports contact attributes mapping for mobile, Android, iPhone, and email clients. For this task, Softaken Excel to VCF Converter is ideal. It preserves number formats, maintains structured contact fields, supports bulk Excel to VCF conversion, and allows offline processing with a free demo for testing before purchase.