Question: how to add ngx-bootstrap in angular 6?
Answer: Installation instructions. ... 
Install ngx-bootstrap from npm: npm install ngx-bootstrap --save. ... 
Add component to your page: <button type="button" class="btn btn-primary" tooltip="Vivamus sagittis lacus vel augue laoreet rutrum faucibus."> ... 
Bootstrap 3 <!-- ... 
Bootstrap 4 <!---