You can add text to a webpage using the paragraph <p> tag. You can then style the text using all kinds of different CSS properties. Some of the most commonly used stylings are: color, to define the text color, font-size, to define the size of the font in number of pixels(px), font-family, to define the type of font you want, such as serif or sans-serif, and text-align, to align the text left, right, or center. For the text color there are some basic names you can enter such as: blue, red, black, etc. or you can enter HEX or RGB color codes.
There are plenty of other ways to add text other than the paragraph <p> tag, but you can easily just use the paragraph tag. There are various sizes of header tags: h1, h2, h3, etc., but they are the same as a paragraph except they have different default font sizes. You can even simply type in text without any tags, but as we'll see later this is a problem because you'll have no way to identify it. You can use units other than pixels(px) to set the font-size, but for now px is sufficient. Also for font-family there are thousands of unique fonts you can choose, but you don't need to know that now. If you're curious you can check out Google Web Fonts