Can I stay in Thailand for 90 days with a one-year visa?

You can stretch this visa for almost 9 months

It's a METV (multiple entry tourist visa) "print" a hard copy, when you arrive in Thailand you will get stamped in for 60 days, and can extend it at your local immigration office "once" for 30 days, then you need to leave, just get a bus to the nearest land border, and bounce out and back to Thailand, and repeat the process when needed, you can do that for 6 months between /24 and /25, remember to do a border bounce just before the end of march, and you can get between 8 and 9 months out of this visa (if you need the extra time) with this visa I did land border bounces, and never got asked to show a ticket leaving Thailand, it is much easier to do an in the country non O visa, and then a 12 month extension based on retirement, but it's ฿800k in the bank for retirement, and ฿400k for marriage.

It’s not a one year visa

When you made the application for which visa have you applied?

Just got the same. Only 60 days on arrival, can go immigration and extend another 30 days then if u wish, I just pop to Cambodia or Vietnam every 60 days for a long weekend. You can get 8 months out of this visa if you leave the country and return by 29th March

This is as Brandon states only a six months multiple entries tourist visa which gives you 60 days upon each entry within six months, -NOT a one year Non O-A visa.

(suggest you remove your email from the image)

This is a multiple entry tourist visa. Every time you enter Thailand until 29 March 2025 you will receive a 60 day tourist entry stamp. Each entry can also be extended by 30 days, giving 90 days total.