Microsoft word replace line break (shift + enter) with paragraph (enter) in without affecting list

If you are saying that you want unnumbered text paragraphs in between the numbered ones, you can apply an unnumbered style to each of those. For example, you can use the List Continue series of built-in styles; you will have to adjust the left indent so that it suits your list.

To make this more easy to maintain, ensure that the numbered paragraphs are indeed formatted with numbered styles. Adding numbering as you go, by using the Numbering button on the Home tab, will be time-consuming and easily broken.

Ok, here is an example of what I am talking about

here is an example as shown by the picture
if as you can see my document was not properly format with enter, so I need to replace shift + enter with enter; if I do from rind and replace it will introduce new number which I don't need. This is the problem I try to solve

see attached image

The Enter key is the standard way to add a new number in a numbered list.

How about if you tell us the bigger picture of what problem you're trying to solve, and we can give you ways to achieve that goal.