Many cameras come with a lens. People call this a “kit lens” and while it can be good for some things (sports, landscape), it’s not really going to give you a professional-looking portrait (in the traditional sense - like the image with the blurry background below). And it’s not going to be useful in low light unless you are using flash.
Perhaps the worst thing about kit lenses is they are nearly impossible to learn on. When you zoom in and out on them, the amount of light the lens lets in changes. And when you are learning it can be really confusing and frustrating.
Considering all this, I highly recommend you learn on a prime lens (no zoom). And for shooting portraits of people or product photos, specifically a 50mm or 35mm (f1.8 or f/1.4).
Here are links to my suggestions (check compatibility prior to purchasing):
If these are not in the budget, I’d check the refurbished gear at your local camera shop or B&H or Adorama.
Send me an email if you have any questions about this or need suggestions for other camera models!