You need to submit caste certificate if it is asked by the institute for submitting for admission requirements. However the caste certificate is not asked by all the categories.  Most of the times the caste certificate is required by reserve categories such as scheduled caste or Scheduled tribe to submit. Along with caste certificate, you need to submit the mentioned below documents as well:

• Marksheet of 10th or 8th class
• Aadhar Card and its details
• Bank account details
• Passport size photographs as per the size asked by ITI Delhi
• Signature