By itself, no. "Wore something formal today," has no subject. In informal writing you could say the sentence has an assumed subject of "I," so for example:
Dear Diary,
Wore something formal today. Went to the party. Had a good time.
But if you add an explicit subject, it's definitely correct:
Jane wore something formal today.
My daughter also wore something formal today.
The sentence "Lets get into something formal today" is not correct grammar due to improper use of preposition.
"Let's wear something formal today" is the correct phrase to use when suggesting that a group of people should dress formally. "Let's get into something formal today" is also acceptable but may sound less natural in this context.
You are leaving early today.
Due to maintenance, this hole is closed today. Today, due to maintenance, this hole is closed.
It is correct.
Meet with Scott and I
"Today's" is the correct form when indicating possession, meaning something that belongs to or is associated with today (e.g., "today's meeting"). "Todays," without the apostrophe, is not standard English and should be avoided in formal writing. Always use "today's" to indicate ownership or relevance to the current day.
Yes, that sentence is grammatically correct. It effectively conveys the message that all the meetings you had planned for today have been canceled.
No. Correct grammar would be "Please forward your report by today at the latest." But it is absurd - no one can hand in a report yesterday. Use Please submit your report by the end of the day today.
Yes, "starting from today" is correct. It indicates that something is beginning on the current day.
The sentence is incorrect as it lacks the proper punctuation. A better sentence would be "I spent less today and I'm happy I was able to save money, even just for one day".
Yes, by the end of today is correct. It's not a complete sentence, though.