How to leave space in between while knitting?


I am trying to make a back cover and I need the gap for my phone camera to be visible. Please help me I am just a beginner.


Welcome to the forum!
You could cast off a couple of sts in the location of the camera and then on the next or the 2nd or 3rd row after the cast off, cast on over the same area. You would have to knit the two sides of the opening with 2 different strands of yarn.