Remove spacing between cols

add a class when you need to remove spaces use it

.padding-0{
    padding-right:0;
    padding-left:0;
}

in html write this class

<div class="row">
   <div class="col-md-2 padding-0">
       //stuff here for this column
   </div>
   <div class="col-md-10 padding-0">
       //stuff here for columns
   </div>
</div>

In Bootstrap 5, the no-gutters class has changed to g-0

In Bootstrap 4, the no-gutters class is included. No extra CSS is needed...

<div class="row no-gutters">
  <div class="col-md-2">
    // stuff here for this column
  </div>
  <div class="col-md-10">
    // stuff here for columns
  </div>
</div>