Depends on the immigration office and by all accounts there are differing reports from Laksi. You may need a printed copy you may not.
Your host probably did file a TM30 but if they did it on your arrival then they won’t be able to retrieve it as the system only allows a search from 7 days ago.
It will take them probably less than 3 minutes to file another one using today’s date and then they can retrieve that and get the pdf print from it.
Immigration won’t care that the TM30 is from today just that you have a filed one.
Im using the term today but that can be tomorrow or the day you actually apply for the extension. It doesn’t matter.
If an immigration officer were to question why it’s a recent date rather than when you arrived you can say I stayed at a friends house last night so my host filed a new one for me today.
Older non updated websites that will still show 30 day visa exempt. Some still show “only 15 days if entering via a land border”. That stopped in 2016.
If you haven’t bought a visa prior to coming to Thailand then you would get stamped in for 60 days on what’s called a visa exempt entry.
You can extend that once for 30 days at a local immigration office. There are over 80 around the country so you use the one that serves the area your TM30 (notice of staying that is filed by the hotel or house owner) is filed.
Depends on the office you use, but generally you’ll need to fill out the TM7 form (for extensions), a copy of your passport, a copy of your entry stamp, a copy of your visa, a passport sized photo a filed TM30 and 1,900 baht.
You won’t need to show an onward travel ticket and there’s an almost zero chance of being denied.