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Excel
A prepared Excel Spreadsheet with the relevant data is required in order to import or update a company. The file should include Contact persons name, and any other fields in order to update existing Contacts data.
Review Exporting data to MS-Excel and MS-WordCreate Excel-file for import and update to better understand how to prepare an excel file from dRofus that could be used in this process.
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To import or update Contacts for companies:
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Select the Company Module
Select the Import/Export tab
Select “Import/ Update Contacts”
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Read more about how to fill in information: Introduction: Import/update with Excel-file
Import, Update or both
Select to either:
Import New
Update existing
Import new and update existing.
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If Importing New, the Excel file must have a column identifying the Contact person ID.
Then, determine which unique key will be used to identify the Company if necessary. A Company is required to import or update Contacts data. 
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Once all of the columns have been mapped select import.