How do I increase the voltage of a circuit that powers and transmits data to an led
To power more LEDs usually requires more current, not more voltage.

The ATMega328 microcontroller in a typical Arduino has IO pins which can provide enough current to illuminate an indicator LED - say 20 mA. The total current is about 100 mA.

To drive more LEDs or higher powered LEDs you can use a transistor to switch current from the Arduino supply of from a separate supply for the LEDS.







simulate this circuit &ndash; Schematic created using CircuitLab

D1 is a LED directly driven by the Arduino - this must be a low current LED and you can't drive many of them directly.

D2 takes it's power from the supply, not from the Arduino IO pins. The IO pin just supplies a small amount of current to turn on the transistor.

D3 is an example where a high-power LED is provided with a separate power supply. This might be a higher voltage supply - e.g. 12 V instead of the Arduino's 5V supply.

As user33855 commented, this example uses Bipolar Junction Transistors (BJTs) which need a resistor to limit base current. In place of Q1 and Q2 you can instead use MOSFETs which don't need R3 and R5.

You wouldn't normally have a mixture as shown, it's simply an illustration of various options.