Best way to linearly step-up MCU output 0-3.3V to 0-5V
Digital

The first step is to make sure you really need 5 V output.  Many digital inputs have a low enough minimum logic high threshold so that 3.3 V is solidly high.

If you really need 5 V logic signals, use level converters.  These are small, cheap, and readily available.  They have a split power supply.  You power one side from the 3.3 V supply and connect it to 3.3 V logic, and power the other side from 5 V and connect it to 5 V logic.

Sometimes the requirements are simple so that this can be achieved with a single transistor.  But, given the level of your question, the best answer is simply "use level converters".

Analog

Converting from 5 V to 3.3 V is easily done with a voltage divider, which is made from two resistors.

For converting from 3.3 V to 5 V, again, first make sure that it's really needed.  If it is, this can be done with a opamp in classic positive gain configuration.  That means signal into the + input, and two resistors that divide the output voltage into the - input.