You don't. Logos should be vectorized, which means that you can size them to match your needs. Special software is required to create vectorized logos, even if you have great design skills to create a logo you love. Simply clicking WordArt in Word and typing some text, or coming up with a design in Microsoft Paint won't create a logo that will serve the interests of your business. More importantly, this isn't something that you should do yourself. It's incredibly difficult and expensive to re-brand later and ultimately, spending a few hundred dollars now on a professionally created logo design will save you tens or hundreds of thousands of dollars in a few years.