Whenever you write a document using a computer, you should basically never use tabs. Ever. If you are writing an outline, this is especially true; if you are going to send the document to another person for any reason, this is doubly especially true.
Also, you should NEVER press enter (or return for Macs) at the end of a line. EVER. Not in a Word document, not in an email. Nope, never. There is no exception to this rule. Ever.
For, you see, if another person needs to make the font bigger or smaller or doesn’t have the font you used, that nice looking little document of yours is going to look like it was produced by someone who is insane. It will be a mess. And, instead of easily formatting it for themselves using a handful of keystrokes, they will have to go line by line through the document reformatting it to make it look like you originally did. So, save everyone the effort and aggravation and learn a few simple techniques.
For more on this, please buy and read twice: The PC is Not a Typewriter or The Mac is Not a Typewriter.