Have you noticed that some people put at the end of their smartphone/tablet email signature line a note about shifting the blame for typos to either autocorrect, or big thumbs/small keyboards?
I suggest that people are less than well served by dodging responsibility for typos. It kind of gives the impression that it might be typical behavior in dodging responsibility in other areas of their life/work.
Ideally, a person would want to give the impression that they willingly accept responsibility, and look forward to more, and that if there is some error made, then they want to know about it and will do their best to avoid that sort of thing in the future.
It's much better to completely omit that sort of thing in the signature. The odds are that your email is error free if you take the time/care to look it over before you send it; and you should if it is to someone with whom you are doing business. If the recipient is a friend, then it's unnecessary to mention it anyway, because they will understand. So, again, the blame-dodging is a less than optimum communication.