How to modify cross reference text in Microsoft Word?

The simplest thing to do is to insert the reference manually.

When you insert a cross-reference to a Figure, etc. Word inserts a hidden bookmark to "cover" the portion of the caption that you want to appear in your reference, then uses a REF field to insert the cross-reference text.

The Insert Cross Reference dialog does not allow you to select either just the number part of the Caption number, or the number + following text, but you can insert your own bookmark manually and reference that.

So for example, if you have

Figure 1.1 Description

and you want a cross-reference that shows

1.1 Description

then

Select the text 1.1 Description in the caption.

Use the Insert tab->Links dropdown->Bookmark button to insert a bookmark. Let's say you call it bmabc

Click where you want the cross-reference to appear.

Click ctrl-F9 (Windows desktop Word) to insert a pair of the special field code brace characters { } (You can't just type them on the keyboard).

Between then, type REF bmabc, so you have

{ REF bmabc }

Use Alt-F9 as needed to toggle between "field code" and "field result" view. Select the field and press F9 to update its value as needed.

If you want the bookmark to be hidden, its name should start with an underscore, e.g. _bmabc. If you want the cross-reference to be hyperlinked, put \h after the bookmark name, so you have

{ REF bmabc \h }

If you just want to have a reference to the number, bookmark the number part instead (incidentally, you will probably notice that in the example you give, the number consists oftwo field codes with a "." in between. But you do the same thing - select the two field codes and the "." and insert a bookmark.

If you need both types of cross-reference, you can create two bookmarks and make references to them.

Because Word uses bookmarks to mark the areas it will use in a cross-reference, it is quite easy to damage the cross-references, e.g. if you type some extra text and a paragraph mark and push the word "Description to a new paragraph, any bookmark Word inserting while creating a cross-reference will likely cover the caption paragraph and the new paragraph. So you have to re-insert the cross-reference (or you could reinsert the bookmark). It's the same for cross-references that you create manually.

As an aside, a difference between cross-references to Captions and cross-references to, say, Headings, is that the latter are usually numbered using Word's automatic numbering features, whereas captions are numbered using field codes. Selecting the parts of an automatic numbering scheme is not so easy, which is probably why Word offers more cross-referencing options for those kind of numbered items.

The solution is also: select unwanted parts of the text, choose Font, and set it to hidden.