Where mismatched formatting usually comes from
Webpages and PDFs carry embedded styling β font, size, color, hyperlinks β that gets copied along with the text whether you want it or not. This becomes especially noticeable once you're compiling a document from several different sources, and the mismatched styles start competing with each other on the page.
A faster habit: set it as your default paste behavior
Word lets you change the default paste behavior under Word Options > Advanced > Cut, copy, and paste, so a regular Ctrl+V always keeps text only from then on, removing the need to remember the shortcut every single time.
Frequently Asked Questions
Does this shortcut also remove hyperlinks?
Yes β pasting as plain text also strips any hyperlink formatting, leaving just the plain wording behind (the visible URL text itself, if there was any, still comes through, just no longer clickable).
Can I still undo it if I paste with formatting by mistake?
Yes, pressing Ctrl+Z immediately after pasting removes it, and you can then paste again using the plain-text shortcut instead.