\usepackage{cmap} is usually what does that: > The cmap package provides character map tables, which make PDF files generated by pdfLATEX both searchable and c

\usepackage{cmap} is usually what does that: > The cmap package provides character map tables, which make PDF files generated by pdfLATEX both searchable and copy-able in acrobat reader and other compliant PDF viewers. (from https://ctan.org/pkg/cmap https://ctan.org/pkg/cmap)