Except

Without the commas, both are correct. The first is more natural.
"All shops except this fruit shop are closed on Sunday."

sir,

All shops,except thisfruit shop,are closed on sunday.

All shops are closed on sunday except this fruit shop.


are both sentence correct.

If you capitalize 'Sunday', they are.

all shops, except this fruit shop, are closed on Sunday.
all shops except this fruit shop are closed on Sunday.

Are both correct and which is preferrable?

The second, in my opinion. is preferable, provided you capitalize "all" thus: All.
You may need to consult a style manual for the rules on commas. I don't happen to know if the commas would actually be incorrect. I see no need for them, however.

With commas:
All shops, except this fruit shop, are closed on Sunday.
All shops are closed on Sunday, except this fruit shop.

Without:
All shops except this fruit shop are closed on Sunday.
All shops are closed on Sunday except this fruit shop.

Now we have 4 choices. Are these all correct and which is the best?

Comma use is a slippery occupation. My opinion is that their function is not mandated, except to make sentences, and the relationships between the parts of sentences, clearer. Thus, comma use can vary with the literary ability of the writer and the literacy of the reader.

That said, if the sentence is clear without, don't clutter it up with superfluous punctuation. Among your four cho

Thank you so much, it is loud and clear.

BMO