When you design an HTML page you can create forms with
tags…
Each form can have multiple fields, for example an username field can be represented like so:
<input type="text" name="user" id="user" autocomplete="off">
You can do the same for password but you would need to change the “type” attribute.
To be more clear the problem in the above example is that when you type your password it is clearly visible and so a guy near you can see your password in the textfield.
For this reason you can change the type to “password” like this:
<input type="password" name="pass" id="pass" autocomplete="off">
This way characters are masked.
Actually this challenge revolves around this concept, so my hint is learn about HTML type Attribute and all the possible attribute values.
This is a good place to start.