When writing for business, it is important that grammar should be correct, but sometimes it is difficult to remember when we should apostrophes and when they are not needed.
The apostrophe is a mark of omission which means that it means that a word has been contracted with a letter or letters being intentionally left out.
So, we use it’s when we mean it is.
’tis can also mean it is.
its is a possessive pronoun, such as its skin. An apostrophe should never be used in this case.