Use
\includegraphics
from the
graphicx
package. If you would follow Thorsten's link, you can find the package manual, which explains how it's done. Here's a direct link to the manual:
graphicx.
I noticed you asked several basic questions. Not a real problem, but I guess it's easier to read a bit in some basic LaTeX introduction before. Posting, let's say, 20 questions and reading 20 answers is perhaps more work than reading some tutorial pages in a row. Of course, you can always ask questions here which aren't directly explaind by most basic LaTeX introductions. Just follow Thorsten's link to find some. So you can write more efficiently and still get help here for real problems.
Stefan