DIVI Builder provides a maximum four columns by default. There are several ways to add columns, one is to use a DIVI plugin but unfortunately the plugin can be limiting in small ways, for example you may lose the ability to duplicate a module and other little nuances sometimes apply.
A quick and simple method is to use divs and float them left. In basic terms all you need to be mindful of is the maths. For example your web page is 1200 pixels wide so if you want six columns that’s 200 pixels allowed for each div.
We will set this up using DIVI text modules but you could use blurbs or possibly code modules
Create a new row with single column and add a text module, and place the code below in it. Then duplicate the module five times so you have six modules in total.
<div style="float: left; width: 200px;">Your content here</div>
Check the result in your browser. If all is good then you can add a class to tidy it up a bit, you could add 5px of padding inside each div for example or whatever. Add content where it says: ‘Your content here’.
For the definitive guide refer to the Elegant Themes post on this subject which discusses how to create the number of columns you might require.