Choosing your first lens
When you purchased your DSLR camera it probably came with what is referred to as a "kit" lens. That simply means that the camera body and the lens were sold as a bundle. Typical lenses that are included in a bundle is are 18-55mm or 70-300mm. These are versatile lenses but they have one major drawback; they do not offer the capacity to shoot at apertures lower than f/3.5 or f4, respectively.
As your photography hobby grows you will probably want to experiment with shooting at lower apertures for lots of reasons:
To create blurry backgrounds
To capture images where there is less light
To have creative control
There are TONS of lenses to help you reach these goals, but here are some go-to choices when you are ready to purchase your first lens. Note that these are "Fixed Length" lenses, meaning that they do not zoom. (You will have to use your manual zoom, also known as your legs!)
50mm lenses capture an image more or less as your eye sees it. There is no distortion.
Just a little wider than a 50mm lens. Canon only. A much cheaper alternative to the 35mm f/2.
These lenses capture images a little wider than what the eye can naturally see, but without so much distortion that is it distracting.
Before purchasing any lens, be sure to check that it is compatible with your camera body. Most manufacturers have easy-to-read guides on their websites! Enjoy!