How do you achieve this inside a text box?

[bschaefer6]

The first line of text doesn't follow the 2-column layout of the text box. Instead, it is placed in as if this was a normal text box without any columns.

[jmlevy · Accepted solution]

That is the span column feature

https://helpx.adobe.com/indesign/using/aligning-text.html#:~:text=Create%20paragraphs%20that%20span%...

[Steve Werner]

@jmlevy is correct!

Here is a good video which explains it:

https://creativepro.com/how-to-span-and-split-text-across-columns-in-indesign/