Tess’ revisions to the report increased it’s readability significantly. Tesss’ revisions to the report increased its readability
significantly. Tess’es revisions to the report increased it’s readability significantly. Tess’ revisions to the report increased its readability significantly.
The sentence that is grammatically correct is: Tess’ revisions to the report increased its readability significantly.
Explanation:
The fourth/last option (sentence) is correct because an apostrophe is required after the noun (Tess) to indicate that the noun (Tess) is possessive; in addition, the word "its" is appropriate, and not in a contracted form—it's—which represents "it is".