If (long) words are splitting as opposed to being moved to the next text line, there might be a problem with the font. Try using a different font. Another possibility is that the document is damaged; see if Open and Repair makes a difference.

All of the commands at the Page Layout | Breaks drop down insert different types of breaks in a Word document; none of these would fix the problem you are describing.

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Stefan Blom
Microsoft Word MVP

Microsoft 365 apps for business
Windows 11 Professional