Arpeggios are simply a broken chord, you play all the notes of the chord, one at a time, to create the sound of the overall chord. Arpeggios are not the same a picking a chord. When you pick a chord you usually will keep your fingers on the fretboard to hold down the chord, arpeggios, on the other hand, are played note for note on their own. Arpeggios can be played in one position only covering one Octave, or you could play them across the whole fretboard covering as much as three Octaves.
A lot of guitar players do use arpeggios for their solos without even being aware of it. The technique of using Arpggios is not new. During the Shred Period of the 1980s and early 90s some guitar players started to use Arpeggios exclusively for their solos. One of the most well-known Arpeggio player is Ingwie Malmsteen. He will play Arpeggios at super speed all across the fretboard. He is just an extreme example of how to use Arpeggios but you can apply them in many other ways.
Why is it a good idea to learn to use Arpeggio shapes for your Solos you may wonder? Arpeggio notes will make you play harmonically, which is one of the hardest things to do for any beginning, improvising guitar player. Most people will hear riffs and licks and other melodic ideas in their head when it comes to playing solos, harmony notes seem to come less natural and you have to work at it. All of this becomes apparent when you start to improvise over more complex chord sequences, as you riffs may no longer make sense.
The whole thing with learning to play the guitar (and learning the fretboard!) is this puzzle idea: At some point all chords and scales fall into place, they will all lead to this similar place where you can draw from to play over any chord sequence. Working on different parts of your playing will help you and as any good guitar player will admit: None of this will happen over night, you need to work at it!.
Okay time to introduce two different Arpeggio shapes: The first shape is simply a C shape in the key of D. The chord is a D7, which is a basic triad—-Root, Maj. Third, Perfect Fifth and Dom. 7th. The Root is on the 5th fret of the A string and the next Ocatave if sound on the 3rd fret of the B string.
Here is the same chord (D7) but now played over three strings to make it more flexible for your fingers:
Root is still on 5th Fret A string , next Ocatave note is now found on the G string 7th fret.
Use for your own playing some other well-known open chord shapes, play them first as conventional chord shape, then experiment with putting some of the notes on other strings to create a different chord shape.
When you start experimenting with various shapes you will soon discover that each shape does have it own advantages and disadvantages: Some of the shapes may include a lot of string skipping, large finger stretches or other issues. Rework them to find out which shapes work for your own playing.
Playing with a lot of different Arpeggio shapes you may discover that most shapes on the guitar can be brought back to those basic, five open chord shapes that you learned in the very beginning. Realising this can be so much of a benefit for learning to visualise the fretboard: Try to recognize the basic open chord shape wherever you are on the fretboard and it will help you to play the notes you want to play.
Have fun with your playing and hope to see you soon back for more.