The post earlier had some basic HTML you'll need, like Bold Text, or Italic Text, or making a link, or making some settings over a text.
But in real game, you'll need a lot more.
Which is why the post is here. I'll write these down before I forgot.

Tag	Result
<form>	*It's incomplete. It needs sub-tags to add the content.*
<input>	*Incomplete. It needs parameters. Explained below. It's sub-tag for <form>.*
<textarea>Text</textarea>	Text *It's another sub-tag for <form>.*
Text<br />Text 2	Text Text 2
Text</p>Text 2	Text Text 2
<hr>

Tips:

• The <form> tag ends with </form>. But be sure to have the <input> or <textarea> before the end tag, because when you click the Submit button, all data from the form tag will be sent, based on the method sent.
• There are 2 data sending methods for <form> which are POST and GET. POST method sends the data through the server, so it's 'invisible'. While the GET method sends the data through URL (URL rewriting). This could be useful in some cases.
• <input> tag had many kinds. You can add parameters to determine its type. Like, add type="text" to make a one-line text entry (e.g. for Username field in Login form). The type="password" makes a password input field. type="submit" type makes a button that sends all the input data from the <form> tag to the </form> tag end. The type="reset" resets all the data input within the two form tags. While type="image" makes an image that works as the type="submit" button (sends all form fields through one of the methods to be processed). Check Archaeozoic Area, then when you can view the whole Home page, right click anywhere and choose 'View page source...', locate the form or input tags, and see what they made. Then choose Register, and do the same. This will get you even deeper understanding about the tags for the form. THESE TAGS ARE VITAL FOR GAMES.