direction and HTML dir: which describes the direction of the text

In a few sentences

In brief

The language direction is also part of the meaning of the document.

Useful to know

CSS direction sets the main direction of the text and influences some aspects of the arrangement. MDN recommends that the attribute dir, be preferred for the HTML content direction whenever possible. [1]

Example: <p dir="rtl"> ... </p> for corresponding content. This does not mean mechanically reversing all characters as in a mirror: mixed numbers and different scripts follow the rules of bidirectional text. For Bulgarian, the usual writing is from left to right. With foreign user content, look at the direction separately from the visual alignment.

Sources

For further detail and to check the information:

[1] MDN — direction ↗