The Sun is 1,391,016 km (864337 mi) in diameter and 146,600,000 km (93,000,000 mi) from us. These facts are consistent with everyday observations.
Flat-Earthers have a different idea about the distance and the size of the Sun. However, on careful examinations, the numbers are inconsistent with everyday observations.
According to some flat Earth sources, the distance from the Equator to the north pole is 6000 miles, and the height of the Sun from the surface is 3000 miles. We can then calculate the distance from an observer on the equator to the Sun is about 14500 km (9000 miles). They also claim that the sun is 32 miles in diameter.
We can compare such figures with the apparent width of the sun and its apparent height from the surface. And as some of them claim the sun can come in front of the clouds, we can throw in the height of clouds for good measure. No matter how we fudge the numbers, everything will be inconsistent.
Some flat Earthers will try to defend and claim the numbers are wrong. But most of them will refuse to give us the correct numbers. And when in the rare cases they do, the numbers will be inconsistent with observation, too.