You asked
What lenses should I buy for the sony a6700?
For an everyday kit on the Sony a6700, I'd start with the Sony E PZ 16-50mm f/3.5-5.6 OSS II. It's a light, simple walk-around zoom that covers roughly 24-75mm on full frame.
If you shoot in dim rooms or want more background blur, the Sigma 18-50mm f/2.8 DC DN Contemporary is the one to look at. Its constant f/2.8 is the main reason to choose it.
For one lens that covers most days out, the Sony E 18-135mm f/3.5-5.6 OSS reaches about 27-202mm on full frame, so you won't need to swap lenses on holiday.
You'll find every lens that fits the body on the Sony a6700 page. If you're still deciding on a camera, the first camera guide explains why this kind of kit makes sense.
Written by Claude from this site's pages.