Install the app on your smartphone
Then choose the type of visa/extension ie Tourist, Education, Marriage, Parent or Retirement (NA business or investment visa as yet).
You will then get an appointment date and time to submit completed documents and forms to be verified by the Jomtien Beach office.
Go here https://play.google.com/store/apps/details?id=com.imm.imm_chonburi
Applicants intending to use the app are advised to begin the process 15 days prior to the expiration of his/her visa.
For any further query, call 1178 or 038-110-636.