Forgot to put the town on the envelope. Will it still get to its destination if everything else is correct?

Yes!

I once received a letter from Saudi Arabia that had the street, house number, zip code, and USA on it. Wasn’t even delayed!

It maybe back in your hands in tomorrow or the ZIP will get it there. I’ve had just my last name and ZIP for a return address and it was returned to me because I forgot the stamp

For my own return address I simply include the house number, street name and ZIP code, and mail has been successfully returned to me – using only that information – many times. I also used to send mail from all over the country to my parents that way, decades ago. Every letter arrived.

Of course, the information then has to be letter-perfect and legible. If I were to include an incorrect town spelling, for example, then that’s not a disaster. If all I have is a ZIP code and part of it is illegible or incorrect, then that IS a disaster (in terms of the mail being delivered properly).

Zip code and street address is all you really need.

The 9 numeral zip code is all you need. 00000–0000

Yup.
The town is included in the zip.
You’re good!

The zip code is really what the Post Office goes by rather than the town (since towns can have multiple zip codes).

Ok, thanks!