Drupal 8 - Pathauto taxonomy terms in content paths
If you have a taxonomy vocabulary named company

And you have a taxonomy entity reference on your basic page machine-named field_company

Then the pattern you want in pathauto is:

[node:field_company:entity:field_short_name]/[node:title]

This says, "find the value of field_company on the current node, get it's referenced entity, find the value of field_short_name / the node title"