You can directly use the footnote tool to mark your modified places to explain the situation, but marking numbers is a better choice. Put it next to the author's name, and look at the magazine for specific meaning. Generally, you can find another text explanation.

Some authors' signatures will be followed by a number or a letter, which is actually a label of authors rank. After all, many SCI papers are written by several authors. Some magazines use Arabic numerals to mark authors, while others use English letters to mark authors, with the same function and purpose.