Originally Posted by: darickmendes

I would like to understand please what exactly pedals does for the guitar that amplifier doesn't and are they really necessary in order to have the guitar sound like most of the rock songs and metal, hope its not silly question haha

The short answer is that it depends on what amp you have & what kind of sound (how much gain) you want to have to play with.

Now for the long answer!

Effects pedals were original created & used to alter the sound in ways that amp could not. Especially with gain, overdrive, distortion type effects. Early tube amps did not have much gain built in without turning them up very loud & even then it was not the same thing as the clipping resulting from an overdrive unit.

Eventually, amp designers & producers added a pre-amp stage built into the amp that could produce more saturated gain. But even then some players wanted more gain! So, they added gain pedals in the signal chain between the guitar & amp!

Nowdays modern amps typically have all the gain (overdrive or distortion) built into the amp so there's no need for any effects pedal to achieve that sound. But there are still some new, modern amp made that are modelled on old style amps. So you might need a gain pedal of some kind. And some players like to set thir amp to a lower level of gain, then add a pedal just to get more gain by stepping on a pedal. Some amps have separate channels, one with more gain, one with less & there is a pedal made for the amp that just has a stomp button to switch between channels as desired.

What kind of amp do you have?

Anders covers gain pedals & all kinds of other effects starting in this lesson of the Rock course.

https://www.guitartricks.com/lesson.php?input=20422&s_id=1616

And there are plenty of YouTube videos that cover the topic as well.

Hope that helps!