Page break is a sign of paging, the previous page ends and the next page begins.
MicrosoftWord can insert automatic page breaks (or hard page breaks), or force page breaks at specified locations by inserting manual page breaks (or soft page breaks).
Section break plays the role of separating the text formats in front of it. If a section break is deleted, the text in front of it will be merged into the later section and the latter format will be adopted.
If you want to delete section break and keep the format before section break, you need to enter the header and footer editing status after section break, select Link to the previous header, exit the header and footer editing status, and then delete section break and keep the format before section break.