hi all in my esp32 i cant find a vin how i can know the pins
this is the photo
The “5V” pin is usually connected to a linear dropout regular (LDO) that generates 3.3V. So that is your “VIN”. I would not put much higher voltages than 5V on it though, as LDOs convert excess voltage to heat, the power dissipation is P = (Vi – Vo) * Io. I.e., higher input voltage, the more the LDO has to drop.
Assume output current Io is 0.1A, Vo = 3.3V and Vi = 5V. Then P = (5V - 3.3V) * 0.1A = 0.17W.
Assume now Vi = 12V. Then P = 0.87W. The package might not be able to handle that.
See e.g.
From https://dl.espressif.com/dl/schematics/esp32_devkitc_v4-sch.pdf.