Mobile Photography

Not impossible if you understand the limitations of your camera.  They're built for ease of use, not precision.  A 10-12 megapixel phone camera will never produce the same results as a 22-44 megapixel digital camera.  That's the physics of it.  But if your phone camera has manual settings, and you have a well-lit environment, and brace your mobile phone to a solid object, and at the proper distance & angle to your subject, you might get some decent shots. You'll need to experiment to see what works and doesn't work with your device.

In the end, all cameras are just a tiny hole in a box that allows light to come in. What goes on before you click the button is more important than the box itself.

If you're serious about Stock photography, start saving now for decent entry-level camera equipment, lenses, lights, a tripod and cleaning kit.  See below.

https://www.bhphotovideo.com/explora/photography/buying-guide/entry-level-cameras-for-aspiring-photographers

I highly recommend enrolling in structured photography & post-editing classes.  You'll learn how to care for your equipment as well as essential camera techniques --- light/aperture, shutter speed, focal-distance, camera angles, composition, focus, and how to enhance your digital photos in post-editing.

Food photography is very challenging, even for experts. Food has to look appealing.  The best food shots incorporate other elements into the frame such as colorful dishes, wood boards, herbs/flowers, woven fabrics & baskets, and highly reflective utensils, which can create their own set of challenges.  No judgement, but food photography isn't for everyone.  It's a special talent.  For reference, look at what other Stock Contributors are doing in the Food keywords.

We can't teach you to be a Stock photographer from this user-to-user community.  You really need to enroll in courses and practice, practice, practice...  But if you stick with it, photography can be an immensely rewarding hobby that will last you a lifetime.

Best of luck.