Caps Lock is a feature that you can see in almost all keyboards, when it is active, it capitalizes each letter which is typed into the keyboard .
When it is off, then all the letters that are typed are always input. At the same time, when it is on, then each letter that is typed is all transmit to an upper-case character. Caps do not alter lock input like the rest of the keys, such as numbers and symbols.
Since caps lock changes the input of letters into a keyboard, it is important that you know whether it is on or off. Therefore manufactures are provided with a light to know its active status on the keyboard, which burns when Caps Lock is on. This shows that Caps Lock is on.
Since passwords are often case-sensitive , take care that caps lock is not active when you are entering any login information. Use Caps Lock only when necessary.