AutoCorrect Options Smart Tag

Check your Options

Check your (Tools > AutoCorrect Options)(AutoCorrect Tab).

Correct Two Initial Capitals

If you type two consecutive uppercase letters at the beginning of a word, the second uppercase letter is automatically changed to a lowercase letter.
For example "CApitals" will be changed to "Capitals". Any words containing capital letters in the middle of words are ignored.
This entry can get automatically added to your exceptions meaning that this word is not

Capitalize first letter of sentences

This will mean that the first letter of every sentence will be automatically changed to a capital letter if it is entered in lowercase.

Capitalize first letter of table cells

Capitalize names of days

The first letter of the days of the week is automatically changed to uppercase, Monday, Tuesday, Wednesday, etc.

Correct accidential usage of caps lock

This will automatically change your text if you have accidentally left the caps lock on.
If Word notices that you are capitalising everything backwards it assumes you must have pressed the Caps Lock accidentally and changing the letters accordingly.
No smart tag appears.

Automatic Correcting

In addition to inserting symbols manually you can use the AutoCorrect feature to do this for you.
Whenever you enter a sequence of symbols the AutoCorrect facility will automatically replace this with the corresponding entry.
There is a large number of entries included in the built-in list.