HOw to convert uppercase letters in lowercase in MS Word

I am not well versed with the computer and haven't had any formal training in MS office. Though I have to do some offline works in MS Word Quite often. Sometimes my Caps Key is on while typing so I have to retype them again in lower case. It is very tasking when you have to do this. So I want to know if there is any feature in MS Word where it can be converted in Lowercase to Uppercase or VIce Versa.
