There different ways to add text in Adobe Muse. First, you need to create a text frame. Then, you can add text by typing inside the text frame, copy/paste the text into the frame or have all your text divided into .txt files which makes you save lots of time and makes the task easier.
Also, in the text panel you can format it. Choose size, font family or color. Align it the way you want and add space in between letter or paragraphs. Once you get all the text you want into your Adobe Muse page, you have to adapt it to your different breakpoints. There is a tool in Muse where you can choose to edit the text in a specific breakpoint or choose to edit it across all breakpoints.
For example, in breakpoint 1200px the title is 36pt. When browser gets smaller, this title might not look good so we will need to decrease the size using the text panel. But if you have a paragraph and the font size is 12pt, it might work and look good in all breakpoints.
Watch the video for more detailed information. You will learn all about how to work with text in Adobe Muse.