Col-md-offset is used to give margin in left in desktop. But for bootstrap 4 , we use offset-md-1. Bootstrap 4 is the upgraded version. So there are some changes in classes.
For Bootstrap 3
col-md-offset-1 // You can change number 1 to 11 according to you. col-lg-offset-1 col-sm-offset-1 col-xs-offset-1
For Bootstrap 4
offset-md-1 offset-sm-1 offset-lg-1 offset-xs-1 //You can change number 1 to 11 according to you.