Raspberry pico. setting SDA, SCL using Arduino ide

setup is a classic 16x2 LCD with i2c module run off a Raspberry Pico and have failed at understanding how to set the gpio 4 and 5 as SDC and SCL using the Arduino ide.
every example and video I have found is in python and they set a value to the pins but I have no idea what function it is for Arduino ide and the syntax for that.

secondly the 3.3v will be enough to set the SDC and SCL lines? I can power the display from the 5v
to have a bright display but do the SDC and SCL have to be logic converted to 5v for the lcd?

There are LCD displays for 3.3V, that will be easier.

A 5V LCD display needs to be powered with 5V. It has probably pullup resistors from SDA to 5V and from SCL to 5V.
In the schematic of Adafruit for the I2C backpack module, they use are 4k7 pullup resistors.
That means that a current from 5V via the 4k7 flows into SDA and SCL. Since the Raspberry Pi Pico does not have 5V tolerant pins, you need a I2C level shifter.

There is an option to connect a 5V display to a 3.3V Raspberry Pi Pico: in a simulation !
This seems to work: PiPlusLCD.ino - Wokwi Arduino Simulator

For the pins, use the most common and default that everyone uses:

Wire.begin();     // use the default, GPIO4 = SDA, GPIO5 = SCL

IF you use Earl's core for Arduino:
https://github.com/earlephilhower/arduino-pico

The docs are here
https://arduino-pico.readthedocs.io/en/latest/

and the examples show:

Wire (I2C0), Wire1 (I2C1)
::setSDA(pin)
::setSCL(pin)