How to hide/restict access to certain field on expense page?

Summary:

We were asked to add Tax code and account field to the expense report creation page. Nevertheless, not all business units require these fields.

Is there a way to create a drop-down with these two fields so only those who need to update these fields would open it?

Any suggestions on how can we make the view more user-friendly so those who don't need to see these fields won't see them?

Content (required):

Version (include the version you are using, if applicable):

Code Snippet (add any code snippets that support your topic, if applicable):