how to remove blue border on button click code example

Example 1: diable focus button css

*:focus {
    outline: 0 !important;
}

Example 2: how to remove border on button click

.btnName{
	outline: none;
}

Example 3: how to remove border from selected button

outline: none;

Example 4: remove button outlines

<button class="btn shadow-none">Bootstrap (4.1) button without shadow</button>