The heading tags only accept 1 attribute - ALIGN. This attribute sets the horizontal alignment of the text heading with respect to the screen. For example, below are headings whose alignments are set to left (default), center, and right respectively.
<H2 [ALIGN=left|center|right]>text</H2>
<H3 [ALIGN=left|center|right]>text</H3>
<H4 [ALIGN=left|center|right]>text</H4>
<H5 [ALIGN=left|center|right]>text</H5>
<H6 [ALIGN=left|center|right]>text</H6>