<BR> forces a line break
this text is on a new line
<CENTER> </CENTER> centers the text it contains. However, you should use an ALIGN="CENTER" attribute with a document text structure instead. Here are some examples:
<P ALIGN="CENTER">
<DIV ALIGN="CENTER>
<NOBSP> will force a long line to stay together rather than wrap
<HR> will display a rule line between segments of text. You can control the size of the rule line with a WIDTH attribute, if desired:
<HR WIDTH="50%"> specifies that the rule be half the size of the current window