Unlike, for instance, Elementor, Divi has no built-in feature to add the last updated date of an article. This makes sense enough since Divi is not built specifically for blogging. In case you need it, this post will show you how.
When creating a custom single post template in WordPress using Divi Builder, you can display the post meta such as author, date, etc,.
But as said above, Divi Builder has no built-in module or setting option to display the last updated date of an article. To display the last updated date of an article in Divi Builder, you can use the Divi Post Data extension.
How to Display the Last Updated Date of an Article in Divi
Divi Post Data is a Divi Builder extension developed by WP Creator’s Club. It is a paid extension which you can get on Divi Marketplace for $5 (can be installed on unlimited sites). In addition to displaying the last updated date of an article, the Divi Post Data extension also allows you to display other information about a blog post. Such as the estimated reading time, word count, and time since the last update. You can display the information via a module called Post Data, which is added by the Divi Post Data extension.
To start using the Divi Post Data extension, make sure you to install it first. Activate the extension right away once installed. Once the extension is installed and activated, you can edit the custom single post template you created with Divi Builder. Or you can also create a new one. On the Divi Builder editor, add a new module by clicking the grey plus icon and select Post Data.

The Post Data settings panel will appear right after you add the Post Data module. On the Type of Data option on the Text block under the Content tab, select Updated Date. Set the prefix and the suffix on the Prefix Text and Suffix Text fields, respectively. You can also set the date format on the Date Format field.

If you want to add an icon, you can open the Image block (also under the Content tab). Enable the Use Icon option and select the icon you want to use use.

Style Up the Module
To style up the Post Data module, you can go to the Design tab on the Post Data module settings panel. First, you can open the Image & Icon block to set the size of the icon, the color of the icon, and the position of the icon.

To set the typography (font family, font size, font style, and so on), you can open the Content Text block (also under the Design tab). From this block, you can also set the text color, alignment, and text shadow.

To set the margin and padding, you can open the Spacing block on the Design tab.

You can explore other blocks on the Design tab to apply more styling options to the Post Data module. Make sure to click the white checklist icon on the bottom-right corner of the settings panel to apply the changes you made. Once you are done editing the single post template, you can update/publish it.