Make sure you understand the difference between an attribute and property and are familiar with the definitions of other HTML terms.

dir="ltr"

left to right

dir="rtl"

right to left

dir="auto"

the direction is determined by the content of the element

The default value of the directionality property when the attribute is not coded on the top element is ltr (left to right). On other elements where the attribute is not coded, the value of the dir property is inherited from the parent element.

The directionality can be overridden with the <bdo> tag (bi-directional override) or the <bdi> tag (bi-directional isolation).