Student or Learner
Is "I closed my business in June" correct?
If you closed it forever, you might want to use something like shut my business down.
As Tdol's post suggests, "I closed my business in June" could be ambiguous. It's possible that you decided to go on holiday for the month of June so you closed your business while you were away and then reopened it in July. That could also be worded "I closed my business for June". If you closed it forever, then "I shut down/closed down/wound up my business in June" could be used.
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.