Dear Sir/Madam,
This email is in reference to the application having reference number __________ (mention number) regarding ____________ (mention application type).
I would like to request you to kindly submit the required documents as soon as possible to avoid any delay in the process of your application. I have attached a list of documents required regarding the same.
Kindly, submit the document at ___________ (contact details) before __/__/____ (date) to avoid any inconvenience. If you have any questions or concerns regarding this, please do not hesitate to contact me at any time.
Regards,
___________ (Name),
___________ (Contact details)