There are a number of videos on YouTube of people using guitars and microphones on the Pure Data and they sound really good.
e.g:
video 1 -->

How do I connect a guitar and a microphone, using the Behringer U-PHORIA UMC202HD board and having good sound quality?

@blurryface
Read the instructions for loading the USB drivers for the Behringer.
They might say..... load the driver for the Behringer onto your computer before plugging it in.... or just plug it in as a driver will be found on the internet when you do that.
Plug in the Mic (Mic input 1) and Guitar (Line input 2) and set line input 2 to INST (instrument).
Connect its USB to your computer.
Turn on the 48V switch on the back if you are using a condenser microphone.
Open Pd and in the Media tab select ASIO (for a PC)........ For other OS's I don't know.... google it.... you are looking for low latency drivers or the delay will be horrible.
Then in Media / Audio Settings select the Behringer with 2 inputs and 2 outputs.
[adc~ 1] will give you the microphone and [adc~ 2] will give you guitar.
[dac~] will return your stereo mix to the Behringer outputs.
David.