Do I Need to Visit Immigration to Extend My Non-B Visa in Bangkok?

You have about 40 days to apply for an 1 year Extension of Stay, talk to your employer. Good luck

You forgot to cover your DOB.

@Jacob ******

your non immigrant visa is signed used and became invalid the day you entered Thailand. This is not a tourist visa, please do not compare tourists and people working in Thailand.

If you decide not to get a one year extension of stay based on employment, you can stay up to July 31 on the amnesty. However, you can not work (unless you already have a work permit), and you will need to get a new Non-B visa when you return.

You'll also need to be careful about which consulate you can use to get another Non-B visa. For example, Vientiane only issues Non-B visas one time each year, if you don't have proof of a cancelled work permit.

I guess you got a new stamp in your passport with the Entry date 20 Mar 2020 and Admitted Until 18 Jun 2020 (this date is a guess, so please check)

You need to get a one year extension of stay based on employment, if you are working. You, and your employer, will go to CW and get the extension of stay based on employment together.