How can I black out text in PDF before sending it to my client?

I have a PDF contract with some private details that need covering up before I send it to the client, but I’m not sure how to do it on my work laptop.

had the same thing last month with an invoice. i opened the pdf in word, deleted the private lines, and saved it as a new pdf. if that messes up the layout i just print the page, black it out with a marker, and scan it. tbh thats what i trust most so nothing is still sitting under a box.