Normally Word opens in Print Layout view, which can be uncomfortable (slower editing, smaller fonts, etc).

Print Layout view is useful before printing and whenever one adjusts the layout of a document, but perhaps during normal writing draft mode is more convenient, unless one writes a few pages only.

Even if you select Draft view, the next time you open Word it still uses layout view! To change this go to Word Options > Advanced > “General”, and mark the checkbox “Allow opening a document in Draft view“.

In this view the lines of a document may flow outside the visible area of the document.

To fix this, go to Word Options > Advanced > “Show document content”, and mark the checkbox “Show text wrapped within the document window“.