Summary: A backwards P is probably a paragraph mark. If you're seeing a backwards P it's easy to turn off, but also tells me you should change something else too.
In my outlook email I now have what looks like a letter "p" and back arrows, at the end of each line! How do I remove them?
What you're seeing are probably paragraph marks.
The fact that you're seeing them is benign, and easy to turn off. But it also tells me a little bit about your configuration.
While it's really a matter of personal preference, I see it as a sign of a larger problem.
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First, you're probably seeing something very similar to this:

The font may be different, so the appearance might not be identical, but at the end of each line is a paragraph mark.
Question 1, of course, is if it's a "paragraph" mark, why is it at the end of every line? This is one of the differences between plain text and "rich" text email. In rich text, each paragraph is represented as a single line - it's then broken into multiple lines as it's displayed to fit the window. Try it sometime in your word processor - resize the window and you'll see each paragraph "re-wrap" to fit the screen.
In plain text, each line is represented by ... a line.
Regardless, at the end of the line, whether it represents an entire paragraph, or just a single line, is an end of line marker.
Or, in word processing terms, an paragraph mark.
So why do I keep coming back to "word processing" when all you're doing is editing email?
Because you're using Microsoft Word as your email editor. And Microsoft Word is first and foremost a word processor.
In Word you can turn off the display of paragraph marks several different ways. In Tools, Options, on the View tab, you'll see the Paragraph marks option:

Simply uncheck that.
If that setting is unchecked already, you may be viewing all non-printable characters. If you see a dot everywhere there's a space, such as between words, this is likely to be the problem. SHIFT+CTRL+* will turn that on and off, including paragraph marks.
Now, you'll note that I said I see this as a sign of a larger problem ... so what's the larger problem?
Using Microsoft Word to edit email.
Word is a fine, fine word processor. I use it regularly. But in my opinion, it's overkill for editing email. Word is a big program packed with lots of features that aren't (or shouldn't be) used in email. If you're close to marginal on memory, Word can be particularly slow. The rich text it produces is notoriously bloated, meaning that the resulting email is much larger than it needs to be to convey the same look and feel to your recipients.
I strongly recommend not using Microsoft Word as your email editor in Outlook.
To turn it off, and use Outlook's internal, "leaner and meaner" editor, in Outlook hit Tools, Options, and in the resulting dialog click on the Mail Format dialog. Then uncheck both "Use Microsoft Office Word 2003 to edit e-mail messages" and "Use Microsoft Office Word 2003 to read Rich Text e-mail messages" (you may see a different version of Word listed depending on what you have installed):

Once you do that email editing and viewing should be a little quicker for you, and your emails will also be smaller in size.
And you won't see any unexpected paragraph marks.
Related:
Ask Leo! - Why is attaching a Word document to email such a bad idea?
Ask Leo! - How should I setup Outlook?
Article C2772 - August 29, 2006
Thank you so very much!! Super Helpful!
Posted by: Olga at August 18, 2008 10:33 AMI KNEW they were Marks but I HATE HATE them...when they showed up in email probably because I am flying about the keyboard and I accidentally tripped them to start...I was going to scream! Thank you, Thank you, Thank YOU for this quick and easy way to get out! HELP was not helping at all! SHIFT+CTRL+* WOW! Bravo
Posted by: Cathyg at October 14, 2008 8:51 AMKindest Regards,
Cathyg
Thank you very much! It solved my problem which was a big headache..
Posted by: john at October 27, 2008 4:58 AMThank You so Much!!! That was driving me carzy and the simple keystroke you provided was like a magic trick!!
Posted by: Jaz at December 9, 2008 6:30 AMThanks! c-sh-* solved my problem within a minute of encountering the issue. Frustration averted! I learn everything via "accidental keystrokes". Yesterday I learned that in Adobe Bridge I can press Space to make items selected for preview go to full screen.
Posted by: Rick Tucker at March 4, 2009 3:13 PMThank you!! I must have turned it on accidentally and didn't know how to undo it. Thank goodness my google search worked!:
Posted by: rich at March 5, 2009 9:04 AMThere are a lot of people that need help with grammar in addition to spelling. Outlook can check spelling, but not grammar. I have forced some people to use Word as their editor so it catches most of their rediculous grammar mistakes.
Posted by: Private viewer at March 19, 2009 1:08 PMhey thanks so much for the info! was getting very annoyed with these backwards P's as i had no idea what had happened!
Posted by: Hayley at April 17, 2009 4:23 AMthanks very much
Awesome tip. Thanks heaps as I could not get rid of the paragraph mark in MS Outlook. Help was no help!.
Posted by: Ingrid at April 26, 2009 8:43 PMI have the same problem but showing paragraph marks is NOT checked in Word. Can you tell me any other method to get rid of the paragraph marks? This problem started yesterday when I tried to copy and paste a screen shot from the Broward County (Florida) Clerk of the Court's Office into an email.
Thanks for any assistance you can provide.
Posted by: Scott Jay at June 5, 2009 2:51 PM