Slurs are fretting hand articulations. They connect tones. They are a way to create legato between tones [connected & smooth]. There are 5 types: pulls, hammers, slides, bends, and vibrato. They are used extensively in soloing and chord playing.
For a pull, we fret & pick the the higher tone, then ‘pluck’ with the fretting hand to sound the lower.
The slide is keeping pressure on a string while changing the fret. We play the first tone, then keep the pressure on to connect to a higher or lower tone. We can also slide chords. The elbow can precede a slide, acting like slack in a rope.
This is in contrast to guiding where we maintain contact with the string while shifting, but not keeping the pressure [this would be a touch].
For a basic hammer, we pick the first tone, but not the second. We hammer – use our fretting hand to press – the second.
For bending strings, we typically support the leading finger with fingers behind. The 3 finger is the most common bending finger. We fret the string and push upward [or downward for inside strings]. Bending is easier towards the middle of the board where the tension is less.
Vibrato is shaking the string so it wavers. This is something we discover through experimentation. The main motion is a wrist wiggle. Vibrato can up and down or side to side. Up and down is most common on electrics and acoustics [tighten/loosen]. Side to side is common on nylon string guitars [lengthen/shorten].