How is SD card insert in camera

Until ~2010, Sony cameras were notoriously incompatible with memory cards other than Memory Stick - Sony stopped making them in 2010, so all that's left is that card with a little wear from your PSP, NOS, used cards, and Chinese junk. I wouldn't buy one of these without confirming SDHC support; SDXC is a bonus. The exception is if you are using it for retro-style photos and can bear the risk of a Chinese card failing. This doesn't have that issue being new enough.

It's under the battery cover. On the Sony a6300 for example, this is how the card goes in: