CSS

css remove blue outline button

button {
  outline: none;
}

remove outline btn

button {
  outline: none;
}
.btn:focus {
  outline: thin dotted;
  outline: 5px auto -webkit-focus-ring-color;
  outline-offset: -2px;
}
.btn:focus {
  outline: none !important;
}

.btn:focus {
  box-shadow: none;
}

remove outline on button click

using outline:none; we can remove that border in chrome

for tailwind css :
outline-none 
focus:outline-none