You would go to the main immigration office website here
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Look for the TM30 (Notification of Foreigner in Residence) online tab (looks like the image I included)
Make SURE you read the user manual/guide as it is not a user friendly system at all (not even for born, bred, rice-fed thaiz and not for foreigners ๐ )
You first need to make a profile to log in use the system
Then you add an address to that profile
Then you can select that address to file a TM30 on a person, save the data
and
after that you can search for/view/export the data you just saved <- which gives you a PDF file that is the receipt of having filed a TM30 online