As @shelvacu said the <pre> html tag preserves whitespaces.
However using it has one serious disadvantage: the tag itself inherits plenty of unnecessary styling from CSS frameworks that are used in project (e.g. Bootstrap).
To preserve whitespaces and avoid inheriting any unnecessary styles use:
<span style="white-space: pre;">Some whitespaced content</span>
what will act exacly like the <pre> tag.
Be aware that white-space: pre remains text ‘as it is’ – if you would like to have additional line break when it’s necessary use: white-space: pre-wrap.
See: w3schools.com CSS white-space Property