Your business partner is required to acquire an Individual Taxpayer Identification Number (ITIN) if they do not have a Social Security Number by completing Form W-7, IRS Application for Individual Taxpayer Identification Number. For more information, see IRS Taxpayer Identification Numbers
The taxpayer identification numbers are required no matter which type of business entity you formed.
Note: It might be advisable for you to file an extension for the partnership return because of the time it takes for IRS to process the ITIN application.
