(from John Gleason's HTML Tutorials with grateful acknowledgement)
<BR>
<BR> tells your browser to go to the beginning of the next line. BR stands
for line BReak. <BR> acts in the same way as the ENTER key on your keyboard.
When you press the ENTER key, the cursor goes to the beginning of the next line.
With <BR>, the browser is also told to go to the beginning of the next
line. Remember that when you save an HTML document, you are saving it as TEXT
ONLY which means that no codes are saved and so your browser will not know when
to end a line and continue on to the next line. The <BR> tag does this
for you.
<P>
<P> for Paragraph tells your browser to insert a blank or empty line and
then begin a new line (a new paragraph). <BR> tells the browser when a
line has ended while <P> tells the browser to leave a blank line and begin
a new paragraph.
<HR>
<HR> puts a line across the page. HR stands for Horizontal Rule. The two
lines you see below were put there with <HR> tags.