You should submit a completed Form W-7, Application for IRS Individual Taxpayer Identification Number, and all required identification documents to the IRS. No tax return is required for a renewal application, however if you have a filing requirement you should file the return with the renewing application to prevent a delay in your refund. All family members who were issued an ITIN may submit a Form W-7 at the same time.
https://www.irs.gov/credits-deductions/individuals/how-do-i-renew-my-itin
