Do you need to know HTML? The answer to that is DEPENDS. I know your like that's not a answer but really it is. How is it a answer? Simply it has to do with how you go about making your site.
Lets say you have a host service that you don't need to know html it has the very basic tools you need to create a link or to bold or italicize a word. The problem is it doesn't allow you to do everything you might want, like changing the color of a word: Red, with the tools it gives you.
So if you want to change the color you will need to know some HTML.
Its not even hard to learn, You could go searching the net on how to do certian HTML codes but not all work with all hosts services, then there is the problem of some codes mess up other ones or wont work with them. and some sites add in extra parts to the HTML code that actually doesn't need to be there, UGG!!
Instead of going crazy looking all over the place for how to do HTML I'm gonna give you a few quick HTML codes that are used often and some resources that you can use to learn quickly how to use HTML.
Ok First thing to know is for these to work you will need to be in your HTML editor ( this normally your start off or defualt editor) On blogger its the edit HTML. The Compose shows you immediately what it will look like and will act more like a email but HTML codes will not work on the compose.
Some of the codes here you may have a button for on the hosting server you may be using if not try these codes out you will be amazed how easy it is.
for a Bold word you type <b>Word(s) to be bold</b> If you notice the <b> is before the words you want bolded this lets the computer know this word is the start of the code. </b> this is at the end of it saying Hey that's where it stops.
If u want it Italicized it is <i> word(s) to be italic </i> as you can see very similar to the bold and you may see a pattern emerging here with the / yep its the thing that says STOP, END, NO MORE.
So for Underlined words its <u> Underlined word here</u>
Can you believe how simple these first few are, ok now for a couple tricky ones Lets say you want to make some words a diffrent color it be <font color="color you want here"> word here</font>. Many websites are going to say you need to use some fancy number code but that's just gets confusing at least for me it is, besides try remembering about 50+ color number codes, just thinking about that is making me see colors.
So those are some very basic HTML codes and will be used most often, There are lots more but I do not have the time or the patience to put all of them down here. So instead I will offer you some really good resources to learn HTML quickly and easily.
Resources
One Hour HTML
HTML Tutorial Videos